2151555391 has 2 divisors, whose sum is σ = 2151555392. Its totient is φ = 2151555390.

The previous prime is 2151555379. The next prime is 2151555407. The reversal of 2151555391 is 1935551512.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2151555391 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 2151555391.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2151555191) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1075777695 + 1075777696.

It is an arithmetic number, because the mean of its divisors is an integer number (1075777696).

Almost surely, 2^2151555391 is an apocalyptic number.

2151555391 is a deficient number, since it is larger than the sum of its proper divisors (1).

2151555391 is an equidigital number, since it uses as much as digits as its factorization.

2151555391 is an evil number, because the sum of its binary digits is even.

The product of its digits is 33750, while the sum is 37.

The square root of 2151555391 is about 46384.8616576572. The cubic root of 2151555391 is about 1290.9740437014.

The spelling of 2151555391 in words is "two billion, one hundred fifty-one million, five hundred fifty-five thousand, three hundred ninety-one".