21462409 has 4 divisors (see below), whose sum is σ = 21919104. Its totient is φ = 21005716.

The previous prime is 21462401. The next prime is 21462433. The reversal of 21462409 is 90426412.

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 21462409 - 2³ = 21462401 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21462401) 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, 228277 + ... + 228370.

It is an arithmetic number, because the mean of its divisors is an integer number (5479776).

Almost surely, 2^21462409 is an apocalyptic number.

It is an amenable number.

21462409 is a deficient number, since it is larger than the sum of its proper divisors (456695).

21462409 is an equidigital number, since it uses as much as digits as its factorization.

21462409 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 456694.

The product of its (nonzero) digits is 3456, while the sum is 28.

The square root of 21462409 is about 4632.7539325978. The cubic root of 21462409 is about 277.9027358445.

The spelling of 21462409 in words is "twenty-one million, four hundred sixty-two thousand, four hundred nine".