81228990051 has 32 divisors (see below), whose sum is σ = 131299334400. Its totient is φ = 49222131840.

The previous prime is 81228990041. The next prime is 81228990061. The reversal of 81228990051 is 15009982218.

It is an interprime number because it is at equal distance from previous prime (81228990041) and next prime (81228990061).

It is not a de Polignac number, because 81228990051 - 2⁶ = 81228989987 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 81228989979 and 81228990006.

It is not an unprimeable number, because it can be changed into a prime (81228990041) 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, 2376555 + ... + 2410491.

It is an arithmetic number, because the mean of its divisors is an integer number (4103104200).

Almost surely, 2^81228990051 is an apocalyptic number.

81228990051 is a deficient number, since it is larger than the sum of its proper divisors (50070344349).

81228990051 is a wasteful number, since it uses less digits than its factorization.

81228990051 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 42016 (or 42010 counting only the distinct ones).

The product of its (nonzero) digits is 103680, while the sum is 45.

The spelling of 81228990051 in words is "eighty-one billion, two hundred twenty-eight million, nine hundred ninety thousand, fifty-one".