56621997 has 10 divisors (see below), whose sum is σ = 84583598. Its totient is φ = 37747944.

The previous prime is 56621993. The next prime is 56622001. The reversal of 56621997 is 79912665.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (56621993) and next prime (56622001).

It can be written as a sum of positive squares in only one way, i.e., 56340036 + 281961 = 7506^2 + 531^2 .

It is not a de Polignac number, because 56621997 - 2² = 56621993 is a prime.

It is a Duffinian number.

It is a nialpdrome in base 13.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (56621993) by changing a digit.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 349438 + ... + 349599.

Almost surely, 2^56621997 is an apocalyptic number.

It is an amenable number.

56621997 is a deficient number, since it is larger than the sum of its proper divisors (27961601).

56621997 is an equidigital number, since it uses as much as digits as its factorization.

56621997 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 699049 (or 699040 counting only the distinct ones).

The product of its digits is 204120, while the sum is 45.

The square root of 56621997 is about 7524.7589330157. The cubic root of 56621997 is about 383.9974975423.

The spelling of 56621997 in words is "fifty-six million, six hundred twenty-one thousand, nine hundred ninety-seven".