221320990 has 16 divisors (see below), whose sum is σ = 434594160. Its totient is φ = 80480320.

The previous prime is 221320969. The next prime is 221320991. The reversal of 221320990 is 99023122.

221320990 is digitally balanced in base 2 and base 3, because in such bases it contains all the possibile digits an equal number of times.

It is a super-2 number, since 2×221320990² = 97965961229160200, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221320991) 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, 1005895 + ... + 1006114.

It is an arithmetic number, because the mean of its divisors is an integer number (27162135).

Almost surely, 2^221320990 is an apocalyptic number.

221320990 is a deficient number, since it is larger than the sum of its proper divisors (213273170).

221320990 is a wasteful number, since it uses less digits than its factorization.

221320990 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2012027.

The product of its (nonzero) digits is 1944, while the sum is 28.

The square root of 221320990 is about 14876.8608920027. The cubic root of 221320990 is about 604.8869310361.

The spelling of 221320990 in words is "two hundred twenty-one million, three hundred twenty thousand, nine hundred ninety".