55697809 has 4 divisors (see below), whose sum is σ = 55754020. Its totient is φ = 55641600.

The previous prime is 55697783. The next prime is 55697821. The reversal of 55697809 is 90879655.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 7700625 + 47997184 = 2775^2 + 6928^2 .

It is a cyclic number.

It is not a de Polignac number, because 55697809 - 2¹³ = 55689617 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (55697309) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 26592 + ... + 28609.

It is an arithmetic number, because the mean of its divisors is an integer number (13938505).

Almost surely, 2^55697809 is an apocalyptic number.

It is an amenable number.

55697809 is a deficient number, since it is larger than the sum of its proper divisors (56211).

55697809 is a wasteful number, since it uses less digits than its factorization.

55697809 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 56210.

The product of its (nonzero) digits is 680400, while the sum is 49.

The square root of 55697809 is about 7463.0964753244. The cubic root of 55697809 is about 381.8968156932.

The spelling of 55697809 in words is "fifty-five million, six hundred ninety-seven thousand, eight hundred nine".