97221791 has 4 divisors (see below), whose sum is σ = 98591184. Its totient is φ = 95852400.

The previous prime is 97221763. The next prime is 97221799. The reversal of 97221791 is 19712279.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 19712279 = 1291 ⋅15269.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-97221791 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (97221799) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 684590 + ... + 684731.

It is an arithmetic number, because the mean of its divisors is an integer number (24647796).

Almost surely, 2^97221791 is an apocalyptic number.

97221791 is a deficient number, since it is larger than the sum of its proper divisors (1369393).

97221791 is a wasteful number, since it uses less digits than its factorization.

97221791 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1369392.

The product of its digits is 15876, while the sum is 38.

The square root of 97221791 is about 9860.1111048507. Note that the first 4 decimals coincide. The cubic root of 97221791 is about 459.8200162286.

The spelling of 97221791 in words is "ninety-seven million, two hundred twenty-one thousand, seven hundred ninety-one".