55857391 has 2 divisors, whose sum is σ = 55857392. Its totient is φ = 55857390.

The previous prime is 55857371. The next prime is 55857421. The reversal of 55857391 is 19375855.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-55857391 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (55857311) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 27928695 + 27928696.

It is an arithmetic number, because the mean of its divisors is an integer number (27928696).

Almost surely, 2^55857391 is an apocalyptic number.

55857391 is a deficient number, since it is larger than the sum of its proper divisors (1).

55857391 is an equidigital number, since it uses as much as digits as its factorization.

55857391 is an evil number, because the sum of its binary digits is even.

The product of its digits is 189000, while the sum is 43.

The square root of 55857391 is about 7473.7802349280. The cubic root of 55857391 is about 382.2611971472.

The spelling of 55857391 in words is "fifty-five million, eight hundred fifty-seven thousand, three hundred ninety-one".