221396397 has 4 divisors (see below), whose sum is σ = 295195200. Its totient is φ = 147597596.

The previous prime is 221396393. The next prime is 221396401. The reversal of 221396397 is 793693122.

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 an interprime number because it is at equal distance from previous prime (221396393) and next prime (221396401).

It is a cyclic number.

It is not a de Polignac number, because 221396397 - 2² = 221396393 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221396393) 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, 36899397 + ... + 36899402.

It is an arithmetic number, because the mean of its divisors is an integer number (73798800).

Almost surely, 2^221396397 is an apocalyptic number.

It is an amenable number.

221396397 is a deficient number, since it is larger than the sum of its proper divisors (73798803).

221396397 is an equidigital number, since it uses as much as digits as its factorization.

221396397 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 73798802.

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

The square root of 221396397 is about 14879.3950481866. The cubic root of 221396397 is about 604.9556209052.

The spelling of 221396397 in words is "two hundred twenty-one million, three hundred ninety-six thousand, three hundred ninety-seven".