81790911 has 32 divisors (see below), whose sum is σ = 124113600. Its totient is φ = 53222400.

The previous prime is 81790909. The next prime is 81790913. The reversal of 81790911 is 11909718.

It is an interprime number because it is at equal distance from previous prime (81790909) and next prime (81790913).

It is not a de Polignac number, because 81790911 - 2¹ = 81790909 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81790913) 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, 242535 + ... + 242871.

It is an arithmetic number, because the mean of its divisors is an integer number (3878550).

Almost surely, 2^81790911 is an apocalyptic number.

81790911 is a deficient number, since it is larger than the sum of its proper divisors (42322689).

81790911 is a wasteful number, since it uses less digits than its factorization.

81790911 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 536 (or 530 counting only the distinct ones).

The product of its (nonzero) digits is 4536, while the sum is 36.

The square root of 81790911 is about 9043.8327605059. The cubic root of 81790911 is about 434.0785727760.

The spelling of 81790911 in words is "eighty-one million, seven hundred ninety thousand, nine hundred eleven".