397721307 has 8 divisors (see below), whose sum is σ = 561488976. Its totient is φ = 249550592.

The previous prime is 397721299. The next prime is 397721347. The reversal of 397721307 is 703127793.

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

It is a cyclic number.

It is not a de Polignac number, because 397721307 - 2³ = 397721299 is a prime.

It is not an unprimeable number, because it can be changed into a prime (397721347) 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, 3899178 + ... + 3899279.

It is an arithmetic number, because the mean of its divisors is an integer number (70186122).

Almost surely, 2^397721307 is an apocalyptic number.

397721307 is a deficient number, since it is larger than the sum of its proper divisors (163767669).

397721307 is a wasteful number, since it uses less digits than its factorization.

397721307 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7798477.

The product of its (nonzero) digits is 55566, while the sum is 39.

The square root of 397721307 is about 19942.9513111776. The cubic root of 397721307 is about 735.4045050008.

The spelling of 397721307 in words is "three hundred ninety-seven million, seven hundred twenty-one thousand, three hundred seven".