2581487021 has 2 divisors, whose sum is σ = 2581487022. Its totient is φ = 2581487020.

The previous prime is 2581487017. The next prime is 2581487047. The reversal of 2581487021 is 1207841852.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 2534014921 + 47472100 = 50339^2 + 6890^2 .

It is a cyclic number.

It is not a de Polignac number, because 2581487021 - 2² = 2581487017 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2581487081) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1290743510 + 1290743511.

It is an arithmetic number, because the mean of its divisors is an integer number (1290743511).

Almost surely, 2^2581487021 is an apocalyptic number.

It is an amenable number.

2581487021 is a deficient number, since it is larger than the sum of its proper divisors (1).

2581487021 is an equidigital number, since it uses as much as digits as its factorization.

2581487021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 35840, while the sum is 38.

The square root of 2581487021 is about 50808.3361368979. The cubic root of 2581487021 is about 1371.7974207343.

The spelling of 2581487021 in words is "two billion, five hundred eighty-one million, four hundred eighty-seven thousand, twenty-one".