53557621991 has 2 divisors, whose sum is σ = 53557621992. Its totient is φ = 53557621990.

The previous prime is 53557621981. The next prime is 53557622023. The reversal of 53557621991 is 19912675535.

53557621991 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 53557621991 - 2⁶ = 53557621927 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (53557621981) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 26778810995 + 26778810996.

It is an arithmetic number, because the mean of its divisors is an integer number (26778810996).

Almost surely, 2^53557621991 is an apocalyptic number.

53557621991 is a deficient number, since it is larger than the sum of its proper divisors (1).

53557621991 is an equidigital number, since it uses as much as digits as its factorization.

53557621991 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2551500, while the sum is 53.

The spelling of 53557621991 in words is "fifty-three billion, five hundred fifty-seven million, six hundred twenty-one thousand, nine hundred ninety-one".