81349888 has 18 divisors (see below), whose sum is σ = 162382514. Its totient is φ = 40674816.

The previous prime is 81349871. The next prime is 81349897. The reversal of 81349888 is 88894318.

It can be written as a sum of positive squares in only one way, i.e., 54641664 + 26708224 = 7392^2 + 5168^2 .

It is a super-2 number, since 2×81349888² = 13235608555225088, which contains 22 as substring.

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, 158631 + ... + 159142.

Almost surely, 2^81349888 is an apocalyptic number.

It is an amenable number.

81349888 is a deficient number, since it is larger than the sum of its proper divisors (81032626).

81349888 is an equidigital number, since it uses as much as digits as its factorization.

81349888 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 317789 (or 317775 counting only the distinct ones).

The product of its digits is 442368, while the sum is 49.

The square root of 81349888 is about 9019.4172760772. The cubic root of 81349888 is about 433.2969710448.

The spelling of 81349888 in words is "eighty-one million, three hundred forty-nine thousand, eight hundred eighty-eight".