20513042991 has 64 divisors (see below), whose sum is σ = 35454412800. Its totient is φ = 11478475008.

The previous prime is 20513042987. The next prime is 20513042999. The reversal of 20513042991 is 19924031502.

It is not a de Polignac number, because 20513042991 - 2² = 20513042987 is a prime.

It is a super-2 number, since 2×20513042991² (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 (20513042999) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 6178830 + ... + 6182148.

It is an arithmetic number, because the mean of its divisors is an integer number (553975200).

Almost surely, 2^20513042991 is an apocalyptic number.

20513042991 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

20513042991 is a deficient number, since it is larger than the sum of its proper divisors (14941369809).

20513042991 is a wasteful number, since it uses less digits than its factorization.

20513042991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4005 (or 3999 counting only the distinct ones).

The product of its (nonzero) digits is 19440, while the sum is 36.

The spelling of 20513042991 in words is "twenty billion, five hundred thirteen million, forty-two thousand, nine hundred ninety-one".