2651890981 has 2 divisors, whose sum is σ = 2651890982. Its totient is φ = 2651890980.

The previous prime is 2651890951. The next prime is 2651890991. The reversal of 2651890981 is 1890981562.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 2562890625 + 89000356 = 50625^2 + 9434^2 .

It is a cyclic number.

It is not a de Polignac number, because 2651890981 - 2⁷ = 2651890853 is a prime.

It is a super-2 number, since 2×2651890981² = 14065051550218284722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2651890921) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1325945490 + 1325945491.

It is an arithmetic number, because the mean of its divisors is an integer number (1325945491).

Almost surely, 2^2651890981 is an apocalyptic number.

It is an amenable number.

2651890981 is a deficient number, since it is larger than the sum of its proper divisors (1).

2651890981 is an equidigital number, since it uses as much as digits as its factorization.

2651890981 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 311040, while the sum is 49.

The square root of 2651890981 is about 51496.5142606759. The cubic root of 2651890981 is about 1384.1565815483.

The spelling of 2651890981 in words is "two billion, six hundred fifty-one million, eight hundred ninety thousand, nine hundred eighty-one".