97640509 has 4 divisors (see below), whose sum is σ = 97669216. Its totient is φ = 97611804.

The previous prime is 97640471. The next prime is 97640513. The reversal of 97640509 is 90504679.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 97640509 - 2⁷ = 97640381 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 (97640519) 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, 8439 + ... + 16324.

It is an arithmetic number, because the mean of its divisors is an integer number (24417304).

Almost surely, 2^97640509 is an apocalyptic number.

It is an amenable number.

97640509 is a deficient number, since it is larger than the sum of its proper divisors (28707).

97640509 is a wasteful number, since it uses less digits than its factorization.

97640509 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28706.

The product of its (nonzero) digits is 68040, while the sum is 40.

The square root of 97640509 is about 9881.3212173272. The cubic root of 97640509 is about 460.4791934555.

The spelling of 97640509 in words is "ninety-seven million, six hundred forty thousand, five hundred nine".