81575494 has 48 divisors (see below), whose sum is σ = 167254416. Its totient is φ = 29332800.

The previous prime is 81575449. The next prime is 81575497. The reversal of 81575494 is 49457518.

It is a super-2 number, since 2×81575494² = 13309122442688072, 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 81575494.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81575497) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 11104 + ... + 16924.

It is an arithmetic number, because the mean of its divisors is an integer number (3484467).

Almost surely, 2^81575494 is an apocalyptic number.

81575494 is an abundant number, since it is smaller than the sum of its proper divisors (85678922).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81575494 is a wasteful number, since it uses less digits than its factorization.

81575494 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5861 (or 5854 counting only the distinct ones).

The product of its digits is 201600, while the sum is 43.

The square root of 81575494 is about 9031.9153007543. The cubic root of 81575494 is about 433.6971525778.

It can be divided in two parts, 81 and 575494, that added together give a palindrome (575575).

The spelling of 81575494 in words is "eighty-one million, five hundred seventy-five thousand, four hundred ninety-four".