81570479 has 4 divisors (see below), whose sum is σ = 82026360. Its totient is φ = 81114600.

The previous prime is 81570473. The next prime is 81570493. The reversal of 81570479 is 97407518.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81570479 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81570473) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 227672 + ... + 228029.

It is an arithmetic number, because the mean of its divisors is an integer number (20506590).

Almost surely, 2^81570479 is an apocalyptic number.

81570479 is a deficient number, since it is larger than the sum of its proper divisors (455881).

81570479 is a wasteful number, since it uses less digits than its factorization.

81570479 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 455880.

The product of its (nonzero) digits is 70560, while the sum is 41.

The square root of 81570479 is about 9031.6376698803. The cubic root of 81570479 is about 433.6882649585.

The spelling of 81570479 in words is "eighty-one million, five hundred seventy thousand, four hundred seventy-nine".