21467905 has 4 divisors (see below), whose sum is σ = 25761492. Its totient is φ = 17174320.

The previous prime is 21467899. The next prime is 21467909. The reversal of 21467905 is 50976412.

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 14107536 + 7360369 = 3756^2 + 2713^2 .

It is not a de Polignac number, because 21467905 - 2⁹ = 21467393 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21467909) 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, 2146786 + ... + 2146795.

It is an arithmetic number, because the mean of its divisors is an integer number (6440373).

Almost surely, 2^21467905 is an apocalyptic number.

It is an amenable number.

21467905 is a deficient number, since it is larger than the sum of its proper divisors (4293587).

21467905 is an equidigital number, since it uses as much as digits as its factorization.

21467905 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4293586.

The product of its (nonzero) digits is 15120, while the sum is 34.

The square root of 21467905 is about 4633.3470623298. The cubic root of 21467905 is about 277.9264551931.

The spelling of 21467905 in words is "twenty-one million, four hundred sixty-seven thousand, nine hundred five".