81353799 has 12 divisors (see below), whose sum is σ = 120377712. Its totient is φ = 52912800.

The previous prime is 81353791. The next prime is 81353819. The reversal of 81353799 is 99735318.

It is a happy number.

It is not a de Polignac number, because 81353799 - 2³ = 81353791 is a prime.

It is a super-2 number, since 2×81353799² = 13236881223464802, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81353791) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 109867 + ... + 110604.

It is an arithmetic number, because the mean of its divisors is an integer number (10031476).

Almost surely, 2^81353799 is an apocalyptic number.

81353799 is a deficient number, since it is larger than the sum of its proper divisors (39023913).

81353799 is a wasteful number, since it uses less digits than its factorization.

81353799 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 220518 (or 220515 counting only the distinct ones).

The product of its digits is 204120, while the sum is 45.

The square root of 81353799 is about 9019.6340834870. The cubic root of 81353799 is about 433.3039147024.

The spelling of 81353799 in words is "eighty-one million, three hundred fifty-three thousand, seven hundred ninety-nine".