66015840 has 96 divisors (see below), whose sum is σ = 226872576. Its totient is φ = 16002560.

The previous prime is 66015827. The next prime is 66015853. The reversal of 66015840 is 4851066.

It is an interprime number because it is at equal distance from previous prime (66015827) and next prime (66015853).

It is a tau number, because it is divible by the number of its divisors (96).

It is a super-2 number, since 2×66015840² = 8716182261811200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 66015798 and 66015807.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 972 + ... + 11531.

It is an arithmetic number, because the mean of its divisors is an integer number (2363256).

Almost surely, 2^66015840 is an apocalyptic number.

66015840 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 66015840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (113436288).

66015840 is an abundant number, since it is smaller than the sum of its proper divisors (160856736).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

66015840 is a wasteful number, since it uses less digits than its factorization.

66015840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12532 (or 12524 counting only the distinct ones).

The product of its (nonzero) digits is 5760, while the sum is 30.

The square root of 66015840 is about 8125.0132307585. The cubic root of 66015840 is about 404.1563293963.

The spelling of 66015840 in words is "sixty-six million, fifteen thousand, eight hundred forty".