21245461 has 4 divisors (see below), whose sum is σ = 22495212. Its totient is φ = 19995712.

The previous prime is 21245459. The next prime is 21245467. The reversal of 21245461 is 16454212.

It is a happy number.

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 17892900 + 3352561 = 4230^2 + 1831^2 .

It is a cyclic number.

It is not a de Polignac number, because 21245461 - 2¹ = 21245459 is a prime.

It is a super-2 number, since 2×21245461² = 902739226205042, 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 (21245467) 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, 624850 + ... + 624883.

It is an arithmetic number, because the mean of its divisors is an integer number (5623803).

Almost surely, 2^21245461 is an apocalyptic number.

It is an amenable number.

21245461 is a deficient number, since it is larger than the sum of its proper divisors (1249751).

21245461 is a wasteful number, since it uses less digits than its factorization.

21245461 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1249750.

The product of its digits is 1920, while the sum is 25.

The square root of 21245461 is about 4609.2798786795. The cubic root of 21245461 is about 276.9631902500.

Adding to 21245461 its reverse (16454212), we get a palindrome (37699673).

The spelling of 21245461 in words is "twenty-one million, two hundred forty-five thousand, four hundred sixty-one".