81421953075 has 36 divisors (see below), whose sum is σ = 146132980968. Its totient is φ = 43336540800.

The previous prime is 81421953049. The next prime is 81421953103. The reversal of 81421953075 is 57035912418.

81421953075 is a `hidden beast` number, since 8 + 1 + 42 + 1 + 9 + 530 + 75 = 666.

It is not a de Polignac number, because 81421953075 - 2²³ = 81413564467 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a self number, because there is not a number n which added to its sum of digits gives 81421953075.

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 258034 + ... + 478983.

Almost surely, 2^81421953075 is an apocalyptic number.

81421953075 is a deficient number, since it is larger than the sum of its proper divisors (64711027893).

81421953075 is a wasteful number, since it uses less digits than its factorization.

81421953075 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 737524 (or 737516 counting only the distinct ones).

The product of its (nonzero) digits is 302400, while the sum is 45.

The spelling of 81421953075 in words is "eighty-one billion, four hundred twenty-one million, nine hundred fifty-three thousand, seventy-five".