221186920 has 16 divisors (see below), whose sum is σ = 497670660. Its totient is φ = 88474752.

The previous prime is 221186897. The next prime is 221186941. The reversal of 221186920 is 29681122.

221186920 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 180150084 + 41036836 = 13422^2 + 6406^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2764797 + ... + 2764876.

Almost surely, 2^221186920 is an apocalyptic number.

221186920 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

221186920 is an abundant number, since it is smaller than the sum of its proper divisors (276483740).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

221186920 is a wasteful number, since it uses less digits than its factorization.

221186920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5529684 (or 5529680 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 31.

The square root of 221186920 is about 14872.3542184820. The cubic root of 221186920 is about 604.7647652294.

The spelling of 221186920 in words is "two hundred twenty-one million, one hundred eighty-six thousand, nine hundred twenty".