51021491399 has 32 divisors (see below), whose sum is σ = 55993006080. Its totient is φ = 46355645952.

The previous prime is 51021491327. The next prime is 51021491401. The reversal of 51021491399 is 99319412015.

It is a de Polignac number, because none of the positive numbers 2^k-51021491399 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51021491099) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 6438962 + ... + 6446880.

It is an arithmetic number, because the mean of its divisors is an integer number (1749781440).

Almost surely, 2^51021491399 is an apocalyptic number.

51021491399 is a deficient number, since it is larger than the sum of its proper divisors (4971514681).

51021491399 is a wasteful number, since it uses less digits than its factorization.

51021491399 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8159.

The product of its (nonzero) digits is 87480, while the sum is 44.

The spelling of 51021491399 in words is "fifty-one billion, twenty-one million, four hundred ninety-one thousand, three hundred ninety-nine".