2551639 has 2 divisors, whose sum is σ = 2551640. Its totient is φ = 2551638.

The previous prime is 2551607. The next prime is 2551651. The reversal of 2551639 is 9361552.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 2551639 - 2⁵ = 2551607 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 2551639.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2555639) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1275819 + 1275820.

It is an arithmetic number, because the mean of its divisors is an integer number (1275820).

2^2551639 is an apocalyptic number.

2551639 is a deficient number, since it is larger than the sum of its proper divisors (1).

2551639 is an equidigital number, since it uses as much as digits as its factorization.

2551639 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 8100, while the sum is 31.

The square root of 2551639 is about 1597.3850506374. The cubic root of 2551639 is about 136.6489850877.

The spelling of 2551639 in words is "two million, five hundred fifty-one thousand, six hundred thirty-nine".