81557276 has 6 divisors (see below), whose sum is σ = 142725240. Its totient is φ = 40778636.

The previous prime is 81557257. The next prime is 81557297. The reversal of 81557276 is 67275518.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10194656 + ... + 10194663.

It is an arithmetic number, because the mean of its divisors is an integer number (23787540).

Almost surely, 2^81557276 is an apocalyptic number.

It is an amenable number.

81557276 is a deficient number, since it is larger than the sum of its proper divisors (61167964).

81557276 is a wasteful number, since it uses less digits than its factorization.

81557276 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20389323 (or 20389321 counting only the distinct ones).

The product of its digits is 117600, while the sum is 41.

The square root of 81557276 is about 9030.9067097385. The cubic root of 81557276 is about 433.6648647644.

The spelling of 81557276 in words is "eighty-one million, five hundred fifty-seven thousand, two hundred seventy-six".