66974699520 has 156 divisors (see below), whose sum is σ = 232151255076. Its totient is φ = 17859870720.

The previous prime is 66974699489. The next prime is 66974699543. The reversal of 66974699520 is 2599647966.

66974699520 is a `hidden beast` number, since 6 + 69 + 7 + 46 + 9 + 9 + 520 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 15383937024 + 51590762496 = 124032^2 + 227136^2 .

It is a super-2 number, since 2×66974699520² (a number of 22 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2640 + ... + 366000.

It is an arithmetic number, because the mean of its divisors is an integer number (1488149071).

Almost surely, 2^66974699520 is an apocalyptic number.

66974699520 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 66974699520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (116075627538).

66974699520 is an abundant number, since it is smaller than the sum of its proper divisors (165176555556).

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

66974699520 is a wasteful number, since it uses less digits than its factorization.

66974699520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 363396 (or 363371 counting only the distinct ones).

The product of its (nonzero) digits is 44089920, while the sum is 63.

The spelling of 66974699520 in words is "sixty-six billion, nine hundred seventy-four million, six hundred ninety-nine thousand, five hundred twenty".