81421085 has 16 divisors (see below), whose sum is σ = 99107712. Its totient is φ = 64209600.

The previous prime is 81421079. The next prime is 81421111. The reversal of 81421085 is 58012418.

It is not a de Polignac number, because 81421085 - 2⁴ = 81421069 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 128720 + ... + 129350.

It is an arithmetic number, because the mean of its divisors is an integer number (6194232).

Almost surely, 2^81421085 is an apocalyptic number.

It is an amenable number.

81421085 is a deficient number, since it is larger than the sum of its proper divisors (17686627).

81421085 is a wasteful number, since it uses less digits than its factorization.

81421085 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 964.

The product of its (nonzero) digits is 2560, while the sum is 29.

The square root of 81421085 is about 9023.3632864914. The cubic root of 81421085 is about 433.4233406065.

The spelling of 81421085 in words is "eighty-one million, four hundred twenty-one thousand, eighty-five".