221397693 has 12 divisors (see below), whose sum is σ = 324473184. Its totient is φ = 134180200.

The previous prime is 221397689. The next prime is 221397697. The reversal of 221397693 is 396793122.

221397693 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (221397689) and next prime (221397697).

It is not a de Polignac number, because 221397693 - 2² = 221397689 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221397697) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 304593 + ... + 305318.

It is an arithmetic number, because the mean of its divisors is an integer number (27039432).

Almost surely, 2^221397693 is an apocalyptic number.

It is an amenable number.

221397693 is a deficient number, since it is larger than the sum of its proper divisors (103075491).

221397693 is a wasteful number, since it uses less digits than its factorization.

221397693 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 609936 (or 609925 counting only the distinct ones).

The product of its digits is 122472, while the sum is 42.

The square root of 221397693 is about 14879.4385982805. The cubic root of 221397693 is about 604.9568013233.

The spelling of 221397693 in words is "two hundred twenty-one million, three hundred ninety-seven thousand, six hundred ninety-three".