81868252 has 24 divisors (see below), whose sum is σ = 147646800. Its totient is φ = 39701376.

The previous prime is 81868249. The next prime is 81868273. The reversal of 81868252 is 25286818.

It is a happy number.

It is a congruent number.

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, 16699 + ... + 21037.

It is an arithmetic number, because the mean of its divisors is an integer number (6151950).

Almost surely, 2^81868252 is an apocalyptic number.

It is an amenable number.

81868252 is a deficient number, since it is larger than the sum of its proper divisors (65778548).

81868252 is a wasteful number, since it uses less digits than its factorization.

81868252 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4485 (or 4483 counting only the distinct ones).

The product of its digits is 61440, while the sum is 40.

The square root of 81868252 is about 9048.1076474587. The cubic root of 81868252 is about 434.2153503804.

The spelling of 81868252 in words is "eighty-one million, eight hundred sixty-eight thousand, two hundred fifty-two".