66971940 has 48 divisors (see below), whose sum is σ = 214311552. Its totient is φ = 15307776.

The previous prime is 66971921. The next prime is 66971951. The reversal of 66971940 is 4917966.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a junction number, because it is equal to n+sod(n) for n = 66971892 and 66971901.

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, 79309 + ... + 80148.

It is an arithmetic number, because the mean of its divisors is an integer number (4464824).

Almost surely, 2^66971940 is an apocalyptic number.

66971940 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

66971940 is an abundant number, since it is smaller than the sum of its proper divisors (147339612).

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

66971940 is a wasteful number, since it uses less digits than its factorization.

66971940 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 159476 (or 159474 counting only the distinct ones).

The product of its (nonzero) digits is 81648, while the sum is 42.

The square root of 66971940 is about 8183.6385550683. The cubic root of 66971940 is about 406.0981021075.

The spelling of 66971940 in words is "sixty-six million, nine hundred seventy-one thousand, nine hundred forty".