81902801 has 4 divisors (see below), whose sum is σ = 81921204. Its totient is φ = 81884400.

The previous prime is 81902791. The next prime is 81902803. The reversal of 81902801 is 10820918.

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

It can be written as a sum of positive squares in 2 ways, for example, as 19571776 + 62331025 = 4424^2 + 7895^2 .

It is a cyclic number.

It is not a de Polignac number, because 81902801 - 2²² = 77708497 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81902803) 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, 2111 + ... + 12971.

It is an arithmetic number, because the mean of its divisors is an integer number (20480301).

Almost surely, 2^81902801 is an apocalyptic number.

It is an amenable number.

81902801 is a deficient number, since it is larger than the sum of its proper divisors (18403).

81902801 is a wasteful number, since it uses less digits than its factorization.

81902801 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18402.

The product of its (nonzero) digits is 1152, while the sum is 29.

The square root of 81902801 is about 9050.0166298190. The cubic root of 81902801 is about 434.2764224728.

The spelling of 81902801 in words is "eighty-one million, nine hundred two thousand, eight hundred one".