81102578 has 4 divisors (see below), whose sum is σ = 121653870. Its totient is φ = 40551288.

The previous prime is 81102559. The next prime is 81102587. The reversal of 81102578 is 87520118.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 77668969 + 3433609 = 8813^2 + 1853^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20275643 + ... + 20275646.

Almost surely, 2^81102578 is an apocalyptic number.

81102578 is a deficient number, since it is larger than the sum of its proper divisors (40551292).

81102578 is a wasteful number, since it uses less digits than its factorization.

81102578 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40551291.

The product of its (nonzero) digits is 4480, while the sum is 32.

The square root of 81102578 is about 9005.6969746933. The cubic root of 81102578 is about 432.8574398192.

The spelling of 81102578 in words is "eighty-one million, one hundred two thousand, five hundred seventy-eight".