21162461 has 4 divisors (see below), whose sum is σ = 22082592. Its totient is φ = 20242332.

The previous prime is 21162439. The next prime is 21162469. The reversal of 21162461 is 16426112.

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 21162461 - 2⁶ = 21162397 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (23), and also a Moran number because the ratio is a prime number: 920107 = 21162461 / (2 + 1 + 1 + 6 + 2 + 4 + 6 + 1).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21162469) 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, 460031 + ... + 460076.

It is an arithmetic number, because the mean of its divisors is an integer number (5520648).

Almost surely, 2^21162461 is an apocalyptic number.

It is an amenable number.

21162461 is a deficient number, since it is larger than the sum of its proper divisors (920131).

21162461 is an equidigital number, since it uses as much as digits as its factorization.

21162461 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 920130.

The product of its digits is 576, while the sum is 23.

The square root of 21162461 is about 4600.2674922226. The cubic root of 21162461 is about 276.6020472945.

Adding to 21162461 its reverse (16426112), we get a palindrome (37588573).

The spelling of 21162461 in words is "twenty-one million, one hundred sixty-two thousand, four hundred sixty-one".