165920559651 has 56 divisors (see below), whose sum is σ = 310151218944. Its totient is φ = 86192469360.

The previous prime is 165920559619. The next prime is 165920559683. The reversal of 165920559651 is 156955029561.

165920559651 is a `hidden beast` number, since 1 + 6 + 5 + 9 + 20 + 559 + 65 + 1 = 666.

It is an interprime number because it is at equal distance from previous prime (165920559619) and next prime (165920559683).

It is not a de Polignac number, because 165920559651 - 2⁵ = 165920559619 is a prime.

It is a super-2 number, since 2×165920559651² (a number of 23 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (165920559611) by changing a digit.

It is a polite number, since it can be written in 55 ways as a sum of consecutive naturals, for example, 1421791 + ... + 1534056.

It is an arithmetic number, because the mean of its divisors is an integer number (5538414624).

Almost surely, 2^165920559651 is an apocalyptic number.

165920559651 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

165920559651 is a deficient number, since it is larger than the sum of its proper divisors (144230659293).

165920559651 is an equidigital number, since it uses as much as digits as its factorization.

165920559651 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2955883 (or 2955868 counting only the distinct ones).

The product of its (nonzero) digits is 3645000, while the sum is 54.

The spelling of 165920559651 in words is "one hundred sixty-five billion, nine hundred twenty million, five hundred fifty-nine thousand, six hundred fifty-one".