2451621021 has 4 divisors (see below), whose sum is σ = 3268828032. Its totient is φ = 1634414012.

The previous prime is 2451621013. The next prime is 2451621023. The reversal of 2451621021 is 1201261542.

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.

It is a cyclic number.

It is not a de Polignac number, because 2451621021 - 2³ = 2451621013 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 2451620982 and 2451621000.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2451621023) 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, 408603501 + ... + 408603506.

It is an arithmetic number, because the mean of its divisors is an integer number (817207008).

Almost surely, 2^2451621021 is an apocalyptic number.

It is an amenable number.

2451621021 is a deficient number, since it is larger than the sum of its proper divisors (817207011).

2451621021 is an equidigital number, since it uses as much as digits as its factorization.

2451621021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 817207010.

The product of its (nonzero) digits is 960, while the sum is 24.

The square root of 2451621021 is about 49513.8467602750. The cubic root of 2451621021 is about 1348.3970037955.

Adding to 2451621021 its reverse (1201261542), we get a palindrome (3652882563).

The spelling of 2451621021 in words is "two billion, four hundred fifty-one million, six hundred twenty-one thousand, twenty-one".