66615420 has 96 divisors (see below), whose sum is σ = 192745728. Its totient is φ = 17183232.

The previous prime is 66615397. The next prime is 66615427. The reversal of 66615420 is 2451666.

It is a super-2 number, since 2×66615420² = 8875228363552800, which contains 22 as substring.

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

It is a zygodrome in base 2.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66615427) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 293347 + ... + 293573.

It is an arithmetic number, because the mean of its divisors is an integer number (2007768).

Almost surely, 2^66615420 is an apocalyptic number.

66615420 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 66615420, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (96372864).

66615420 is an abundant number, since it is smaller than the sum of its proper divisors (126130308).

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

66615420 is a wasteful number, since it uses less digits than its factorization.

66615420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 379 (or 377 counting only the distinct ones).

The product of its (nonzero) digits is 8640, while the sum is 30.

The square root of 66615420 is about 8161.8270013521. The cubic root of 66615420 is about 405.3762088788.

The spelling of 66615420 in words is "sixty-six million, six hundred fifteen thousand, four hundred twenty".