81913407 has 8 divisors (see below), whose sum is σ = 109494576. Its totient is φ = 54470592.

The previous prime is 81913399. The next prime is 81913421. The reversal of 81913407 is 70431918.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 81913407 - 2³ = 81913399 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81913457) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 33198 + ... + 35579.

It is an arithmetic number, because the mean of its divisors is an integer number (13686822).

Almost surely, 2^81913407 is an apocalyptic number.

81913407 is a deficient number, since it is larger than the sum of its proper divisors (27581169).

81913407 is a wasteful number, since it uses less digits than its factorization.

81913407 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 69177.

The product of its (nonzero) digits is 6048, while the sum is 33.

The square root of 81913407 is about 9050.6025766244. The cubic root of 81913407 is about 434.2951671998.

The spelling of 81913407 in words is "eighty-one million, nine hundred thirteen thousand, four hundred seven".