81158980645 has 16 divisors (see below), whose sum is σ = 103431221568. Its totient is φ = 60923301120.

The previous prime is 81158980633. The next prime is 81158980667. The reversal of 81158980645 is 54608985118.

It is not a de Polignac number, because 81158980645 - 2²³ = 81150592037 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1414179 + ... + 1470448.

It is an arithmetic number, because the mean of its divisors is an integer number (6464451348).

Almost surely, 2^81158980645 is an apocalyptic number.

81158980645 is a gapful number since it is divisible by the number (85) formed by its first and last digit.

It is an amenable number.

81158980645 is a deficient number, since it is larger than the sum of its proper divisors (22272240923).

81158980645 is a wasteful number, since it uses less digits than its factorization.

81158980645 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2884980.

The product of its (nonzero) digits is 2764800, while the sum is 55.

The spelling of 81158980645 in words is "eighty-one billion, one hundred fifty-eight million, nine hundred eighty thousand, six hundred forty-five".