21426407 has 4 divisors (see below), whose sum is σ = 21882336. Its totient is φ = 20970480.

The previous prime is 21426401. The next prime is 21426413. The reversal of 21426407 is 70462412.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (21426401) and next prime (21426413).

It is a cyclic number.

It is not a de Polignac number, because 21426407 - 2⁶ = 21426343 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21426401) 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, 227894 + ... + 227987.

It is an arithmetic number, because the mean of its divisors is an integer number (5470584).

Almost surely, 2^21426407 is an apocalyptic number.

21426407 is a deficient number, since it is larger than the sum of its proper divisors (455929).

21426407 is an equidigital number, since it uses as much as digits as its factorization.

21426407 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 455928.

The product of its (nonzero) digits is 2688, while the sum is 26.

The square root of 21426407 is about 4628.8667079535. The cubic root of 21426407 is about 277.7472600725.

Adding to 21426407 its reverse (70462412), we get a palindrome (91888819).

The spelling of 21426407 in words is "twenty-one million, four hundred twenty-six thousand, four hundred seven".