97821591 has 24 divisors (see below), whose sum is σ = 153448560. Its totient is φ = 55262592.

The previous prime is 97821589. The next prime is 97821601. The reversal of 97821591 is 19512879.

It is not a de Polignac number, because 97821591 - 2¹ = 97821589 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (97821511) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 9345 + ... + 16821.

It is an arithmetic number, because the mean of its divisors is an integer number (6393690).

Almost surely, 2^97821591 is an apocalyptic number.

97821591 is a deficient number, since it is larger than the sum of its proper divisors (55626969).

97821591 is a wasteful number, since it uses less digits than its factorization.

97821591 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7583 (or 7576 counting only the distinct ones).

The product of its digits is 45360, while the sum is 42.

The square root of 97821591 is about 9890.4798164700. The cubic root of 97821591 is about 460.7636826138.

The spelling of 97821591 in words is "ninety-seven million, eight hundred twenty-one thousand, five hundred ninety-one".