2501921891 has 4 divisors (see below), whose sum is σ = 2859339312. Its totient is φ = 2144504472.

The previous prime is 2501921861. The next prime is 2501921911. The reversal of 2501921891 is 1981291052.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 2501921891 - 2⁶ = 2501921827 is a prime.

It is a super-2 number, since 2×2501921891² = 12519226297330031762, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2501921801) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 178708700 + ... + 178708713.

It is an arithmetic number, because the mean of its divisors is an integer number (714834828).

Almost surely, 2^2501921891 is an apocalyptic number.

2501921891 is a deficient number, since it is larger than the sum of its proper divisors (357417421).

2501921891 is an equidigital number, since it uses as much as digits as its factorization.

2501921891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 357417420.

The product of its (nonzero) digits is 12960, while the sum is 38.

The square root of 2501921891 is about 50019.2152177541. The cubic root of 2501921891 is about 1357.5565068667.

The spelling of 2501921891 in words is "two billion, five hundred one million, nine hundred twenty-one thousand, eight hundred ninety-one".