221521794 has 16 divisors (see below), whose sum is σ = 477124032. Its totient is φ = 68160528.

The previous prime is 221521793. The next prime is 221521799. The reversal of 221521794 is 497125122.

It is not an unprimeable number, because it can be changed into a prime (221521793) 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, 1419934 + ... + 1420089.

It is an arithmetic number, because the mean of its divisors is an integer number (29820252).

Almost surely, 2^221521794 is an apocalyptic number.

221521794 is an abundant number, since it is smaller than the sum of its proper divisors (255602238).

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

221521794 is a wasteful number, since it uses less digits than its factorization.

221521794 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2840041.

The product of its digits is 10080, while the sum is 33.

The square root of 221521794 is about 14883.6082318771. The cubic root of 221521794 is about 605.0698132218.

The spelling of 221521794 in words is "two hundred twenty-one million, five hundred twenty-one thousand, seven hundred ninety-four".