2501991 has 6 divisors (see below), whose sum is σ = 3614000. Its totient is φ = 1667988.

The previous prime is 2501987. The next prime is 2501999. The reversal of 2501991 is 1991052.

It is a happy number.

It is not a de Polignac number, because 2501991 - 2² = 2501987 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2501999) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 138991 + ... + 139008.

2^2501991 is an apocalyptic number.

2501991 is a deficient number, since it is larger than the sum of its proper divisors (1112009).

2501991 is a wasteful number, since it uses less digits than its factorization.

2501991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 278005 (or 278002 counting only the distinct ones).

The product of its (nonzero) digits is 810, while the sum is 27.

The square root of 2501991 is about 1581.7683142610. The cubic root of 2501991 is about 135.7569006392.

The spelling of 2501991 in words is "two million, five hundred one thousand, nine hundred ninety-one".