81900313679 has 4 divisors (see below), whose sum is σ = 82012969584. Its totient is φ = 81787657776.

The previous prime is 81900313657. The next prime is 81900313699. The reversal of 81900313679 is 97631300918.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 81900313679 - 2⁸ = 81900313423 is a prime.

It is a super-2 number, since 2×81900313679² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81900313609) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 56326862 + ... + 56328315.

It is an arithmetic number, because the mean of its divisors is an integer number (20503242396).

Almost surely, 2^81900313679 is an apocalyptic number.

81900313679 is a deficient number, since it is larger than the sum of its proper divisors (112655905).

81900313679 is a wasteful number, since it uses less digits than its factorization.

81900313679 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 112655904.

The product of its (nonzero) digits is 244944, while the sum is 47.

The spelling of 81900313679 in words is "eighty-one billion, nine hundred million, three hundred thirteen thousand, six hundred seventy-nine".