221978331 has 12 divisors (see below), whose sum is σ = 322249200. Its totient is φ = 147240720.

The previous prime is 221978291. The next prime is 221978357. The reversal of 221978331 is 133879122.

It is not a de Polignac number, because 221978331 - 2²³ = 213589723 is a prime.

It is a super-2 number, since 2×221978331² = 98548758867091122, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (221978381) 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, 60180 + ... + 63761.

It is an arithmetic number, because the mean of its divisors is an integer number (26854100).

Almost surely, 2^221978331 is an apocalyptic number.

221978331 is a deficient number, since it is larger than the sum of its proper divisors (100270869).

221978331 is a wasteful number, since it uses less digits than its factorization.

221978331 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 124146 (or 124143 counting only the distinct ones).

The product of its digits is 18144, while the sum is 36.

The square root of 221978331 is about 14898.9372439782. The cubic root of 221978331 is about 605.4851932810.

The spelling of 221978331 in words is "two hundred twenty-one million, nine hundred seventy-eight thousand, three hundred thirty-one".