2501921861 has 2 divisors, whose sum is σ = 2501921862. Its totient is φ = 2501921860.

The previous prime is 2501921857. The next prime is 2501921911. The reversal of 2501921861 is 1681291052.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 2189304100 + 312617761 = 46790^2 + 17681^2 .

It is a cyclic number.

It is not a de Polignac number, because 2501921861 - 2² = 2501921857 is a prime.

It is a super-2 number, since 2×2501921861² = 12519225997099406642, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2501921801) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1250960930 + 1250960931.

It is an arithmetic number, because the mean of its divisors is an integer number (1250960931).

Almost surely, 2^2501921861 is an apocalyptic number.

It is an amenable number.

2501921861 is a deficient number, since it is larger than the sum of its proper divisors (1).

2501921861 is an equidigital number, since it uses as much as digits as its factorization.

2501921861 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 8640, while the sum is 35.

The square root of 2501921861 is about 50019.2149178693. The cubic root of 2501921861 is about 1357.5565014406.

The spelling of 2501921861 in words is "two billion, five hundred one million, nine hundred twenty-one thousand, eight hundred sixty-one".