81557274 has 16 divisors (see below), whose sum is σ = 165412800. Its totient is φ = 26802720.

The previous prime is 81557257. The next prime is 81557297. The reversal of 81557274 is 47275518.

It is a super-2 number, since 2×81557274² = 13303177884622152, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 95299 + ... + 96150.

It is an arithmetic number, because the mean of its divisors is an integer number (10338300).

Almost surely, 2^81557274 is an apocalyptic number.

81557274 is an abundant number, since it is smaller than the sum of its proper divisors (83855526).

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

81557274 is a wasteful number, since it uses less digits than its factorization.

81557274 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 191525.

The product of its digits is 78400, while the sum is 39.

The square root of 81557274 is about 9030.9065990077. The cubic root of 81557274 is about 433.6648612195.

The spelling of 81557274 in words is "eighty-one million, five hundred fifty-seven thousand, two hundred seventy-four".