81626419535842 has 16 divisors (see below), whose sum is σ = 126667802943864. Its totient is φ = 39423530320000.

The previous prime is 81626419535839. The next prime is 81626419535893. The reversal of 81626419535842 is 24853591462618.

It can be written as a sum of positive squares in 4 ways, for example, as 64234758886281 + 17391660649561 = 8014659^2 + 4170331^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4927933009 + ... + 4927949572.

Almost surely, 2^{81626419535842} is an apocalyptic number.

81626419535842 is a gapful number since it is divisible by the number (82) formed by its first and last digit.

81626419535842 is a deficient number, since it is larger than the sum of its proper divisors (45041383408022).

81626419535842 is a wasteful number, since it uses less digits than its factorization.

81626419535842 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9855882725.

The product of its digits is 99532800, while the sum is 64.

The spelling of 81626419535842 in words is "eighty-one trillion, six hundred twenty-six billion, four hundred nineteen million, five hundred thirty-five thousand, eight hundred forty-two".