81370530 has 24 divisors (see below), whose sum is σ = 211563612. Its totient is φ = 21698784.

The previous prime is 81370507. The next prime is 81370561. The reversal of 81370530 is 3507318.

It can be written as a sum of positive squares in 2 ways, for example, as 78269409 + 3101121 = 8847^2 + 1761^2 .

It is a junction number, because it is equal to n+sod(n) for n = 81370494 and 81370503.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 451969 + ... + 452148.

Almost surely, 2^81370530 is an apocalyptic number.

81370530 is an abundant number, since it is smaller than the sum of its proper divisors (130193082).

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

81370530 is a wasteful number, since it uses less digits than its factorization.

81370530 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 904130 (or 904127 counting only the distinct ones).

The product of its (nonzero) digits is 2520, while the sum is 27.

The square root of 81370530 is about 9020.5615124559. The cubic root of 81370530 is about 433.3336166994. Note that the first 3 decimals are identical.

Adding to 81370530 its reverse (3507318), we get a palindrome (84877848).

The spelling of 81370530 in words is "eighty-one million, three hundred seventy thousand, five hundred thirty".