81900313658 has 4 divisors (see below), whose sum is σ = 122850470490. Its totient is φ = 40950156828.

The previous prime is 81900313657. The next prime is 81900313699. The reversal of 81900313658 is 85631300918.

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

It can be written as a sum of positive squares in only one way, i.e., 73136170969 + 8764142689 = 270437^2 + 93617^2 .

It is a super-2 number, since 2×81900313658² (a number of 23 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (81900313657) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20475078413 + ... + 20475078416.

Almost surely, 2^81900313658 is an apocalyptic number.

81900313658 is a deficient number, since it is larger than the sum of its proper divisors (40950156832).

81900313658 is a wasteful number, since it uses less digits than its factorization.

81900313658 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40950156831.

The product of its (nonzero) digits is 155520, while the sum is 44.

The spelling of 81900313658 in words is "eighty-one billion, nine hundred million, three hundred thirteen thousand, six hundred fifty-eight".