81261478458 has 24 divisors (see below), whose sum is σ = 176138584128. Its totient is φ = 27076075272.

The previous prime is 81261478427. The next prime is 81261478489. The reversal of 81261478458 is 85487416218.

81261478458 is a `hidden beast` number, since 8 + 12 + 614 + 7 + 8 + 4 + 5 + 8 = 666.

It is an interprime number because it is at equal distance from previous prime (81261478427) and next prime (81261478489).

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 878416 + ... + 966507.

It is an arithmetic number, because the mean of its divisors is an integer number (7339107672).

Almost surely, 2^81261478458 is an apocalyptic number.

81261478458 is an abundant number, since it is smaller than the sum of its proper divisors (94877105670).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81261478458 is a wasteful number, since it uses less digits than its factorization.

81261478458 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1847378 (or 1847375 counting only the distinct ones).

The product of its digits is 3440640, while the sum is 54.

The spelling of 81261478458 in words is "eighty-one billion, two hundred sixty-one million, four hundred seventy-eight thousand, four hundred fifty-eight".