221920156 has 12 divisors (see below), whose sum is σ = 393830640. Its totient is φ = 109397120.

The previous prime is 221920141. The next prime is 221920199. The reversal of 221920156 is 651029122.

It is a congruent number.

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, 390421 + ... + 390988.

It is an arithmetic number, because the mean of its divisors is an integer number (32819220).

Almost surely, 2^221920156 is an apocalyptic number.

It is an amenable number.

221920156 is a deficient number, since it is larger than the sum of its proper divisors (171910484).

221920156 is a wasteful number, since it uses less digits than its factorization.

221920156 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 781484 (or 781482 counting only the distinct ones).

The product of its (nonzero) digits is 2160, while the sum is 28.

The square root of 221920156 is about 14896.9847955887. The cubic root of 221920156 is about 605.4322944560.

Adding to 221920156 its reverse (651029122), we get a palindrome (872949278).

The spelling of 221920156 in words is "two hundred twenty-one million, nine hundred twenty thousand, one hundred fifty-six".