91551921 has 8 divisors (see below), whose sum is σ = 122126880. Its totient is φ = 61005792.

The previous prime is 91551917. The next prime is 91551931. The reversal of 91551921 is 12915519.

It is a happy number.

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

It is not a de Polignac number, because 91551921 - 2² = 91551917 is a prime.

It is not an unprimeable number, because it can be changed into a prime (91551931) 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, 1821 + ... + 13653.

It is an arithmetic number, because the mean of its divisors is an integer number (15265860).

Almost surely, 2^91551921 is an apocalyptic number.

It is an amenable number.

91551921 is a deficient number, since it is larger than the sum of its proper divisors (30574959).

91551921 is a wasteful number, since it uses less digits than its factorization.

91551921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14415.

The product of its digits is 4050, while the sum is 33.

The square root of 91551921 is about 9568.2768041064. The cubic root of 91551921 is about 450.7016560017.

The spelling of 91551921 in words is "ninety-one million, five hundred fifty-one thousand, nine hundred twenty-one".