2516421581 has 2 divisors, whose sum is σ = 2516421582. Its totient is φ = 2516421580.

The previous prime is 2516421539. The next prime is 2516421587. The reversal of 2516421581 is 1851246152.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 2127976900 + 388444681 = 46130^2 + 19709^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2516421581 is a prime.

It is a super-2 number, since 2×2516421581² = 12664755146645079122, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2516421587) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1258210790 + 1258210791.

It is an arithmetic number, because the mean of its divisors is an integer number (1258210791).

Almost surely, 2^2516421581 is an apocalyptic number.

It is an amenable number.

2516421581 is a deficient number, since it is larger than the sum of its proper divisors (1).

2516421581 is an equidigital number, since it uses as much as digits as its factorization.

2516421581 is an evil number, because the sum of its binary digits is even.

The product of its digits is 19200, while the sum is 35.

The square root of 2516421581 is about 50163.9470237341. The cubic root of 2516421581 is about 1360.1739939225.

The spelling of 2516421581 in words is "two billion, five hundred sixteen million, four hundred twenty-one thousand, five hundred eighty-one".