91945990 has 16 divisors (see below), whose sum is σ = 168626448. Its totient is φ = 36084256.

The previous prime is 91945981. The next prime is 91945991. The reversal of 91945990 is 9954919.

It is a self number, because there is not a number n which added to its sum of digits gives 91945990.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91945991) 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, 86212 + ... + 87271.

It is an arithmetic number, because the mean of its divisors is an integer number (10539153).

Almost surely, 2^91945990 is an apocalyptic number.

91945990 is a deficient number, since it is larger than the sum of its proper divisors (76680458).

91945990 is a wasteful number, since it uses less digits than its factorization.

91945990 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 173543.

The product of its (nonzero) digits is 131220, while the sum is 46.

The square root of 91945990 is about 9588.8471674128. The cubic root of 91945990 is about 451.3473855135.

The spelling of 91945990 in words is "ninety-one million, nine hundred forty-five thousand, nine hundred ninety".