221081021 has 8 divisors (see below), whose sum is σ = 255166464. Its totient is φ = 187621200.

The previous prime is 221081009. The next prime is 221081027. The reversal of 221081021 is 120180122.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 221081021 - 2¹⁸ = 220818877 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221081027) 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, 155645 + ... + 157058.

It is an arithmetic number, because the mean of its divisors is an integer number (31895808).

Almost surely, 2^221081021 is an apocalyptic number.

It is an amenable number.

221081021 is a deficient number, since it is larger than the sum of its proper divisors (34085443).

221081021 is a wasteful number, since it uses less digits than its factorization.

221081021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 312811.

The product of its (nonzero) digits is 64, while the sum is 17.

The square root of 221081021 is about 14868.7935287299. The cubic root of 221081021 is about 604.6682341936.

The spelling of 221081021 in words is "two hundred twenty-one million, eighty-one thousand, twenty-one".