561221217 has 40 divisors (see below), whose sum is σ = 865453952. Its totient is φ = 362167200.

The previous prime is 561221203. The next prime is 561221233. The reversal of 561221217 is 712122165.

561221217 is a `hidden beast` number, since 5 + 612 + 21 + 21 + 7 = 666.

It is not a de Polignac number, because 561221217 - 2¹⁶ = 561155681 is a prime.

It is a super-2 number, since 2×561221217² = 629938508821922178, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (561221237) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 811842 + ... + 812532.

Almost surely, 2^561221217 is an apocalyptic number.

It is an amenable number.

561221217 is a deficient number, since it is larger than the sum of its proper divisors (304232735).

561221217 is a wasteful number, since it uses less digits than its factorization.

561221217 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1011 (or 1002 counting only the distinct ones).

The product of its digits is 1680, while the sum is 27.

The square root of 561221217 is about 23690.1079989096. The cubic root of 561221217 is about 824.8557896695.

The spelling of 561221217 in words is "five hundred sixty-one million, two hundred twenty-one thousand, two hundred seventeen".