55991669 has 2 divisors, whose sum is σ = 55991670. Its totient is φ = 55991668.

The previous prime is 55991603. The next prime is 55991681. The reversal of 55991669 is 96619955.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 55204900 + 786769 = 7430^2 + 887^2 .

It is a cyclic number.

It is not a de Polignac number, because 55991669 - 2¹² = 55987573 is a prime.

It is a super-2 number, since 2×55991669² = 6270133994811122, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (55991869) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 27995834 + 27995835.

It is an arithmetic number, because the mean of its divisors is an integer number (27995835).

Almost surely, 2^55991669 is an apocalyptic number.

It is an amenable number.

55991669 is a deficient number, since it is larger than the sum of its proper divisors (1).

55991669 is an equidigital number, since it uses as much as digits as its factorization.

55991669 is an evil number, because the sum of its binary digits is even.

The product of its digits is 656100, while the sum is 50.

The square root of 55991669 is about 7482.7581144923. The cubic root of 55991669 is about 382.5672634354.

The spelling of 55991669 in words is "fifty-five million, nine hundred ninety-one thousand, six hundred sixty-nine".