81202172 has 24 divisors (see below), whose sum is σ = 145083120. Its totient is φ = 39755520.

The previous prime is 81202171. The next prime is 81202243. The reversal of 81202172 is 27120218.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81202171) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 79022 + ... + 80042.

It is an arithmetic number, because the mean of its divisors is an integer number (6045130).

Almost surely, 2^81202172 is an apocalyptic number.

It is an amenable number.

81202172 is a deficient number, since it is larger than the sum of its proper divisors (63880948).

81202172 is a wasteful number, since it uses less digits than its factorization.

81202172 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1421 (or 1419 counting only the distinct ones).

The product of its (nonzero) digits is 448, while the sum is 23.

The square root of 81202172 is about 9011.2247780199. The cubic root of 81202172 is about 433.0345503813.

The spelling of 81202172 in words is "eighty-one million, two hundred two thousand, one hundred seventy-two".