2545810021 has 4 divisors (see below), whose sum is σ = 2545919712. Its totient is φ = 2545700332.

The previous prime is 2545809991. The next prime is 2545810031. The reversal of 2545810021 is 1200185452.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 2545810021 - 2⁵ = 2545809989 is a prime.

It is a super-2 number, since 2×2545810021² = 12962297326048040882, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2545810031) 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, 4825 + ... + 71518.

It is an arithmetic number, because the mean of its divisors is an integer number (636479928).

Almost surely, 2^2545810021 is an apocalyptic number.

It is an amenable number.

2545810021 is a deficient number, since it is larger than the sum of its proper divisors (109691).

2545810021 is an equidigital number, since it uses as much as digits as its factorization.

2545810021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 109690.

The product of its (nonzero) digits is 3200, while the sum is 28.

The square root of 2545810021 is about 50456.0206615623. The cubic root of 2545810021 is about 1365.4485184065.

Adding to 2545810021 its reverse (1200185452), we get a palindrome (3745995473).

The spelling of 2545810021 in words is "two billion, five hundred forty-five million, eight hundred ten thousand, twenty-one".