55640509 has 2 divisors, whose sum is σ = 55640510. Its totient is φ = 55640508.

The previous prime is 55640477. The next prime is 55640521. The reversal of 55640509 is 90504655.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 43599609 + 12040900 = 6603^2 + 3470^2 .

It is a cyclic number.

It is not a de Polignac number, because 55640509 - 2⁵ = 55640477 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (55640579) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 27820254 + 27820255.

It is an arithmetic number, because the mean of its divisors is an integer number (27820255).

Almost surely, 2^55640509 is an apocalyptic number.

It is an amenable number.

55640509 is a deficient number, since it is larger than the sum of its proper divisors (1).

55640509 is an equidigital number, since it uses as much as digits as its factorization.

55640509 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 27000, while the sum is 34.

The square root of 55640509 is about 7459.2565983481. The cubic root of 55640509 is about 381.7658099662.

The spelling of 55640509 in words is "fifty-five million, six hundred forty thousand, five hundred nine".