55643639 has 2 divisors, whose sum is σ = 55643640. Its totient is φ = 55643638.

The previous prime is 55643633. The next prime is 55643681. The reversal of 55643639 is 93634655.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 55643639 - 2²⁰ = 54595063 is a prime.

It is a super-2 number, since 2×55643639² = 6192429122324642, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 55643596 and 55643605.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (55643633) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 27821819 + 27821820.

It is an arithmetic number, because the mean of its divisors is an integer number (27821820).

Almost surely, 2^55643639 is an apocalyptic number.

55643639 is a deficient number, since it is larger than the sum of its proper divisors (1).

55643639 is an equidigital number, since it uses as much as digits as its factorization.

55643639 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 291600, while the sum is 41.

The square root of 55643639 is about 7459.4664018279. The cubic root of 55643639 is about 381.7729684472.

The spelling of 55643639 in words is "fifty-five million, six hundred forty-three thousand, six hundred thirty-nine".