81928501 has 2 divisors, whose sum is σ = 81928502. Its totient is φ = 81928500.

The previous prime is 81928487. The next prime is 81928519. The reversal of 81928501 is 10582918.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 81884401 + 44100 = 9049^2 + 210^2 .

It is a cyclic number.

It is not a de Polignac number, because 81928501 - 2¹³ = 81920309 is a prime.

It is a super-2 number, since 2×81928501² = 13424558552214002, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81928541) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40964250 + 40964251.

It is an arithmetic number, because the mean of its divisors is an integer number (40964251).

Almost surely, 2^81928501 is an apocalyptic number.

It is an amenable number.

81928501 is a deficient number, since it is larger than the sum of its proper divisors (1).

81928501 is an equidigital number, since it uses as much as digits as its factorization.

81928501 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5760, while the sum is 34.

The square root of 81928501 is about 9051.4364053447. The cubic root of 81928501 is about 434.3218410940.

The spelling of 81928501 in words is "eighty-one million, nine hundred twenty-eight thousand, five hundred one".