81902210 has 16 divisors (see below), whose sum is σ = 158764536. Its totient is φ = 30240768.

The previous prime is 81902167. The next prime is 81902239. The reversal of 81902210 is 1220918.

It can be written as a sum of positive squares in 4 ways, for example, as 37319881 + 44582329 = 6109^2 + 6677^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 314879 + ... + 315138.

Almost surely, 2^81902210 is an apocalyptic number.

81902210 is a deficient number, since it is larger than the sum of its proper divisors (76862326).

81902210 is a wasteful number, since it uses less digits than its factorization.

81902210 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 630037.

The product of its (nonzero) digits is 288, while the sum is 23.

The square root of 81902210 is about 9049.9839778864. The cubic root of 81902210 is about 434.2753779095.

The spelling of 81902210 in words is "eighty-one million, nine hundred two thousand, two hundred ten".