81256519450 has 48 divisors (see below), whose sum is σ = 158308546176. Its totient is φ = 30971124800.

The previous prime is 81256519433. The next prime is 81256519483. The reversal of 81256519450 is 5491565218.

It is a Harshad number since it is a multiple of its sum of digits (46).

It is a self number, because there is not a number n which added to its sum of digits gives 81256519450.

It is an unprimeable number.

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 23 ways as a sum of consecutive naturals, for example, 168120 + ... + 436780.

It is an arithmetic number, because the mean of its divisors is an integer number (3298094712).

Almost surely, 2^81256519450 is an apocalyptic number.

81256519450 is a deficient number, since it is larger than the sum of its proper divisors (77052026726).

81256519450 is a wasteful number, since it uses less digits than its factorization.

81256519450 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 268959 (or 268954 counting only the distinct ones).

The product of its (nonzero) digits is 432000, while the sum is 46.

The spelling of 81256519450 in words is "eighty-one billion, two hundred fifty-six million, five hundred nineteen thousand, four hundred fifty".