55721803 has 2 divisors, whose sum is σ = 55721804. Its totient is φ = 55721802.

The previous prime is 55721797. The next prime is 55721819. The reversal of 55721803 is 30812755.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-55721803 is a prime.

It is not a weakly prime, because it can be changed into another prime (55721863) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 27860901 + 27860902.

It is an arithmetic number, because the mean of its divisors is an integer number (27860902).

Almost surely, 2^55721803 is an apocalyptic number.

55721803 is a deficient number, since it is larger than the sum of its proper divisors (1).

55721803 is an equidigital number, since it uses as much as digits as its factorization.

55721803 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 8400, while the sum is 31.

The square root of 55721803 is about 7464.7038119406. The cubic root of 55721803 is about 381.9516467950.

The spelling of 55721803 in words is "fifty-five million, seven hundred twenty-one thousand, eight hundred three".