97720909 has 16 divisors (see below), whose sum is σ = 115295040. Its totient is φ = 81653760.

The previous prime is 97720873. The next prime is 97720957. The reversal of 97720909 is 90902779.

It is a cyclic number.

It is not a de Polignac number, because 97720909 - 2⁹ = 97720397 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 (97720969) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 35422 + ... + 38080.

It is an arithmetic number, because the mean of its divisors is an integer number (7205940).

Almost surely, 2^97720909 is an apocalyptic number.

It is an amenable number.

97720909 is a deficient number, since it is larger than the sum of its proper divisors (17574131).

97720909 is a wasteful number, since it uses less digits than its factorization.

97720909 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2940.

The product of its (nonzero) digits is 71442, while the sum is 43.

The square root of 97720909 is about 9885.3886620608. The cubic root of 97720909 is about 460.6055493788.

The spelling of 97720909 in words is "ninety-seven million, seven hundred twenty thousand, nine hundred nine".