2561427391 has 2 divisors, whose sum is σ = 2561427392. Its totient is φ = 2561427390.

The previous prime is 2561427371. The next prime is 2561427409. The reversal of 2561427391 is 1937241652.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 2561427391 - 2²³ = 2553038783 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2561427331) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1280713695 + 1280713696.

It is an arithmetic number, because the mean of its divisors is an integer number (1280713696).

Almost surely, 2^2561427391 is an apocalyptic number.

2561427391 is a deficient number, since it is larger than the sum of its proper divisors (1).

2561427391 is an equidigital number, since it uses as much as digits as its factorization.

2561427391 is an evil number, because the sum of its binary digits is even.

The product of its digits is 90720, while the sum is 40.

The square root of 2561427391 is about 50610.5462428534. The cubic root of 2561427391 is about 1368.2349605469.

The spelling of 2561427391 in words is "two billion, five hundred sixty-one million, four hundred twenty-seven thousand, three hundred ninety-one".