81964799 has 6 divisors (see below), whose sum is σ = 95346864. Its totient is φ = 70255500.

The previous prime is 81964777. The next prime is 81964807. The reversal of 81964799 is 99746918.

It is a happy number.

It is not a de Polignac number, because 81964799 - 2⁸ = 81964543 is a prime.

It is a super-2 number, since 2×81964799² = 13436456550220802, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 81964799.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81967799) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 836327 + ... + 836424.

It is an arithmetic number, because the mean of its divisors is an integer number (15891144).

Almost surely, 2^81964799 is an apocalyptic number.

81964799 is a deficient number, since it is larger than the sum of its proper divisors (13382065).

81964799 is a wasteful number, since it uses less digits than its factorization.

81964799 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1672765 (or 1672758 counting only the distinct ones).

The product of its digits is 979776, while the sum is 53.

The square root of 81964799 is about 9053.4412794252. The cubic root of 81964799 is about 434.3859729747.

The spelling of 81964799 in words is "eighty-one million, nine hundred sixty-four thousand, seven hundred ninety-nine".