81961453574 has 192 divisors, whose sum is σ = 172068079680. Its totient is φ = 28774932480.

The previous prime is 81961453573. The next prime is 81961453591. The reversal of 81961453574 is 47535416918.

It is a Smith number, since the sum of its digits (53) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81961453573) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 115601132 + ... + 115601840.

It is an arithmetic number, because the mean of its divisors is an integer number (896187915).

Almost surely, 2^81961453574 is an apocalyptic number.

81961453574 is an abundant number, since it is smaller than the sum of its proper divisors (90106626106).

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

81961453574 is a wasteful number, since it uses less digits than its factorization.

81961453574 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 935 (or 928 counting only the distinct ones).

The product of its digits is 3628800, while the sum is 53.

It can be divided in two parts, 81961 and 453574, that added together give a palindrome (535535).

The spelling of 81961453574 in words is "eighty-one billion, nine hundred sixty-one million, four hundred fifty-three thousand, five hundred seventy-four".