81573577 has 8 divisors (see below), whose sum is σ = 83170080. Its totient is φ = 79984320.

The previous prime is 81573553. The next prime is 81573581. The reversal of 81573577 is 77537518.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 81573577 - 2⁷ = 81573449 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81573587) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 24577 + ... + 27697.

It is an arithmetic number, because the mean of its divisors is an integer number (10396260).

Almost surely, 2^81573577 is an apocalyptic number.

It is an amenable number.

81573577 is a deficient number, since it is larger than the sum of its proper divisors (1596503).

81573577 is a wasteful number, since it uses less digits than its factorization.

81573577 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3623.

The product of its digits is 205800, while the sum is 43.

The square root of 81573577 is about 9031.8091764607. The cubic root of 81573577 is about 433.6937552995.

The spelling of 81573577 in words is "eighty-one million, five hundred seventy-three thousand, five hundred seventy-seven".