561672621 has 12 divisors (see below), whose sum is σ = 811564572. Its totient is φ = 374328576.

The previous prime is 561672619. The next prime is 561672677. The reversal of 561672621 is 126276165.

It is a happy number.

561672621 is a `hidden beast` number, since 561 + 6 + 72 + 6 + 21 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 230614596 + 331058025 = 15186^2 + 18195^2 .

It is not a de Polignac number, because 561672621 - 2¹ = 561672619 is a prime.

It is a super-2 number, since 2×561672621² = 630952266362019282, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (561672611) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 26845 + ... + 42941.

It is an arithmetic number, because the mean of its divisors is an integer number (67630381).

Almost surely, 2^561672621 is an apocalyptic number.

It is an amenable number.

561672621 is a deficient number, since it is larger than the sum of its proper divisors (249891951).

561672621 is a wasteful number, since it uses less digits than its factorization.

561672621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19980 (or 19977 counting only the distinct ones).

The product of its digits is 30240, while the sum is 36.

The square root of 561672621 is about 23699.6333515943. The cubic root of 561672621 is about 825.0768809896.

The spelling of 561672621 in words is "five hundred sixty-one million, six hundred seventy-two thousand, six hundred twenty-one".