80491861621 has 2 divisors, whose sum is σ = 80491861622. Its totient is φ = 80491861620.

The previous prime is 80491861609. The next prime is 80491861643. The reversal of 80491861621 is 12616819408.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 66918446596 + 13573415025 = 258686^2 + 116505^2 .

It is a cyclic number.

It is not a de Polignac number, because 80491861621 - 2³³ = 71901927029 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (80491861601) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40245930810 + 40245930811.

It is an arithmetic number, because the mean of its divisors is an integer number (40245930811).

Almost surely, 2^80491861621 is an apocalyptic number.

It is an amenable number.

80491861621 is a deficient number, since it is larger than the sum of its proper divisors (1).

80491861621 is an equidigital number, since it uses as much as digits as its factorization.

80491861621 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 165888, while the sum is 46.

The spelling of 80491861621 in words is "eighty billion, four hundred ninety-one million, eight hundred sixty-one thousand, six hundred twenty-one".