81557430 has 32 divisors (see below), whose sum is σ = 196535808. Its totient is φ = 21660000.

The previous prime is 81557423. The next prime is 81557431. The reversal of 81557430 is 3475518.

It is a super-2 number, since 2×81557430² = 13303228776409800, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 81557391 and 81557400.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81557431) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2115 + ... + 12945.

It is an arithmetic number, because the mean of its divisors is an integer number (6141744).

Almost surely, 2^81557430 is an apocalyptic number.

81557430 is an abundant number, since it is smaller than the sum of its proper divisors (114978378).

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

81557430 is a wasteful number, since it uses less digits than its factorization.

81557430 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11092.

The product of its (nonzero) digits is 16800, while the sum is 33.

The square root of 81557430 is about 9030.9152360101. The cubic root of 81557430 is about 433.6651377192.

The spelling of 81557430 in words is "eighty-one million, five hundred fifty-seven thousand, four hundred thirty".