81560420 has 24 divisors (see below), whose sum is σ = 174182400. Its totient is φ = 32070752.

The previous prime is 81560393. The next prime is 81560443. The reversal of 81560420 is 2406518.

It is a super-2 number, since 2×81560420² = 13304204221152800, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 81560420.

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, 33380 + ... + 35739.

It is an arithmetic number, because the mean of its divisors is an integer number (7257600).

Almost surely, 2^81560420 is an apocalyptic number.

It is an amenable number.

81560420 is an abundant number, since it is smaller than the sum of its proper divisors (92621980).

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

81560420 is a wasteful number, since it uses less digits than its factorization.

81560420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 69187 (or 69185 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 26.

The square root of 81560420 is about 9031.0807769613. The cubic root of 81560420 is about 433.6704372278.

Adding to 81560420 its reverse (2406518), we get a palindrome (83966938).

The spelling of 81560420 in words is "eighty-one million, five hundred sixty thousand, four hundred twenty".