19956465991 has 24 divisors (see below), whose sum is σ = 25312781312. Its totient is φ = 15399450000.

The previous prime is 19956465983. The next prime is 19956466001.

It is a happy number.

19956465991 is nontrivially palindromic in base 10.

It is not a de Polignac number, because 19956465991 - 2³ = 19956465983 is a prime.

It is a super-2 number, since 2×19956465991² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19956465931) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 27135 + ... + 201616.

Almost surely, 2^19956465991 is an apocalyptic number.

19956465991 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

19956465991 is a deficient number, since it is larger than the sum of its proper divisors (5356315321).

19956465991 is a wasteful number, since it uses less digits than its factorization.

19956465991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 228883 (or 228872 counting only the distinct ones).

The product of its digits is 23619600, while the sum is 64.

The spelling of 19956465991 in words is "nineteen billion, nine hundred fifty-six million, four hundred sixty-five thousand, nine hundred ninety-one".