2421561 has 4 divisors (see below), whose sum is σ = 3228752. Its totient is φ = 1614372.

The previous prime is 2421553. The next prime is 2421577. The reversal of 2421561 is 1651242.

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 not a de Polignac number, because 2421561 - 2³ = 2421553 is a prime.

It is an Ulam number.

It is a D-number.

It is a Duffinian number.

2421561 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (2421511) 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, 403591 + ... + 403596.

It is an arithmetic number, because the mean of its divisors is an integer number (807188).

2^2421561 is an apocalyptic number.

It is an amenable number.

2421561 is a deficient number, since it is larger than the sum of its proper divisors (807191).

2421561 is an equidigital number, since it uses as much as digits as its factorization.

2421561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 807190.

The product of its digits is 480, while the sum is 21.

The square root of 2421561 is about 1556.1365621307. The cubic root of 2421561 is about 134.2863298922.

The spelling of 2421561 in words is "two million, four hundred twenty-one thousand, five hundred sixty-one".