81928901 has 2 divisors, whose sum is σ = 81928902. Its totient is φ = 81928900.

The previous prime is 81928879. The next prime is 81928919. The reversal of 81928901 is 10982918.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 80550625 + 1378276 = 8975^2 + 1174^2 .

It is a cyclic number.

It is not a de Polignac number, because 81928901 - 2¹⁸ = 81666757 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81928501) 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, 40964450 + 40964451.

It is an arithmetic number, because the mean of its divisors is an integer number (40964451).

Almost surely, 2^81928901 is an apocalyptic number.

It is an amenable number.

81928901 is a deficient number, since it is larger than the sum of its proper divisors (1).

81928901 is an equidigital number, since it uses as much as digits as its factorization.

81928901 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 10368, while the sum is 38.

The square root of 81928901 is about 9051.4585012582. The cubic root of 81928901 is about 434.3225479235.

The spelling of 81928901 in words is "eighty-one million, nine hundred twenty-eight thousand, nine hundred one".