81057669 has 16 divisors (see below), whose sum is σ = 134745600. Its totient is φ = 42107760.

The previous prime is 81057661. The next prime is 81057673. The reversal of 81057669 is 96675018.

It is not a de Polignac number, because 81057669 - 2³ = 81057661 is a prime.

It is a super-2 number, since 2×81057669² = 13140691407427122, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 81057669.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81057661) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 175219 + ... + 175680.

It is an arithmetic number, because the mean of its divisors is an integer number (8421600).

Almost surely, 2^81057669 is an apocalyptic number.

It is an amenable number.

81057669 is a deficient number, since it is larger than the sum of its proper divisors (53687931).

81057669 is a wasteful number, since it uses less digits than its factorization.

81057669 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 350920.

The product of its (nonzero) digits is 90720, while the sum is 42.

The square root of 81057669 is about 9003.2032632836. The cubic root of 81057669 is about 432.7775295608. Note that the first 3 decimals are identical.

The spelling of 81057669 in words is "eighty-one million, fifty-seven thousand, six hundred sixty-nine".