81917355 has 32 divisors (see below), whose sum is σ = 141926400. Its totient is φ = 40106880.

The previous prime is 81917347. The next prime is 81917357. The reversal of 81917355 is 55371918.

It is not a de Polignac number, because 81917355 - 2³ = 81917347 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is not an unprimeable number, because it can be changed into a prime (81917357) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 37750 + ... + 39860.

It is an arithmetic number, because the mean of its divisors is an integer number (4435200).

Almost surely, 2^81917355 is an apocalyptic number.

81917355 is a deficient number, since it is larger than the sum of its proper divisors (60009045).

81917355 is a wasteful number, since it uses less digits than its factorization.

81917355 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2331.

The product of its digits is 37800, while the sum is 39.

The square root of 81917355 is about 9050.8206810211. The cubic root of 81917355 is about 434.3021443636.

The spelling of 81917355 in words is "eighty-one million, nine hundred seventeen thousand, three hundred fifty-five".