661528072620 has 72 divisors (see below), whose sum is σ = 2112247541040. Its totient is φ = 167122880640.

The previous prime is 661528072607. The next prime is 661528072687. The reversal of 661528072620 is 26270825166.

661528072620 is a `hidden beast` number, since 6 + 6 + 15 + 2 + 8 + 0 + 7 + 2 + 620 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 96711211 + ... + 96718050.

Almost surely, 2^661528072620 is an apocalyptic number.

661528072620 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

661528072620 is an abundant number, since it is smaller than the sum of its proper divisors (1450719468420).

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

661528072620 is a wasteful number, since it uses less digits than its factorization.

661528072620 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 193429295 (or 193429290 counting only the distinct ones).

The product of its (nonzero) digits is 483840, while the sum is 45.

Adding to 661528072620 its reverse (26270825166), we get a palindrome (687798897786).

The spelling of 661528072620 in words is "six hundred sixty-one billion, five hundred twenty-eight million, seventy-two thousand, six hundred twenty".