81241564 has 6 divisors (see below), whose sum is σ = 142172744. Its totient is φ = 40620780.

The previous prime is 81241553. The next prime is 81241571. The reversal of 81241564 is 46514218.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10155192 + ... + 10155199.

Almost surely, 2^81241564 is an apocalyptic number.

It is an amenable number.

81241564 is a deficient number, since it is larger than the sum of its proper divisors (60931180).

81241564 is a wasteful number, since it uses less digits than its factorization.

81241564 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20310395 (or 20310393 counting only the distinct ones).

The product of its digits is 7680, while the sum is 31.

The square root of 81241564 is about 9013.4102314274. The cubic root of 81241564 is about 433.1045622171.

The spelling of 81241564 in words is "eighty-one million, two hundred forty-one thousand, five hundred sixty-four".