2531644021 has 4 divisors (see below), whose sum is σ = 2573146444. Its totient is φ = 2490141600.

The previous prime is 2531644019. The next prime is 2531644051. The reversal of 2531644021 is 1204461352.

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

It can be written as a sum of positive squares in 2 ways, for example, as 662032900 + 1869611121 = 25730^2 + 43239^2 .

It is a cyclic number.

It is not a de Polignac number, because 2531644021 - 2¹ = 2531644019 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2531644051) 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, 20751120 + ... + 20751241.

It is an arithmetic number, because the mean of its divisors is an integer number (643286611).

Almost surely, 2^2531644021 is an apocalyptic number.

It is an amenable number.

2531644021 is a deficient number, since it is larger than the sum of its proper divisors (41502423).

2531644021 is an equidigital number, since it uses as much as digits as its factorization.

2531644021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 41502422.

The product of its (nonzero) digits is 5760, while the sum is 28.

The square root of 2531644021 is about 50315.4451535510. The cubic root of 2531644021 is about 1362.9111553921.

The spelling of 2531644021 in words is "two billion, five hundred thirty-one million, six hundred forty-four thousand, twenty-one".