65620139987781 has 32 divisors (see below), whose sum is σ = 97786408896000. Its totient is φ = 43490253348864.

The previous prime is 65620139987723. The next prime is 65620139987791. The reversal of 65620139987781 is 18778993102656.

65620139987781 is a `hidden beast` number, since 65 + 6 + 20 + 1 + 399 + 87 + 7 + 81 = 666.

It is not a de Polignac number, because 65620139987781 - 2⁷ = 65620139987653 is a prime.

It is a super-2 number, since 2×65620139987781² (a number of 28 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (65620139987791) 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, 4747516 + ... + 12400773.

It is an arithmetic number, because the mean of its divisors is an integer number (3055825278000).

Almost surely, 2^{65620139987781} is an apocalyptic number.

It is an amenable number.

65620139987781 is a deficient number, since it is larger than the sum of its proper divisors (32166268908219).

65620139987781 is a wasteful number, since it uses less digits than its factorization.

65620139987781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17149130 (or 17149124 counting only the distinct ones).

The product of its (nonzero) digits is 274337280, while the sum is 72.

The spelling of 65620139987781 in words is "sixty-five trillion, six hundred twenty billion, one hundred thirty-nine million, nine hundred eighty-seven thousand, seven hundred eighty-one".