21623407 has 8 divisors (see below), whose sum is σ = 23327136. Its totient is φ = 19925472.

The previous prime is 21623389. The next prime is 21623411. The reversal of 21623407 is 70432612.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21623407 - 2⁷ = 21623279 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 (21623477) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9318 + ... + 11404.

It is an arithmetic number, because the mean of its divisors is an integer number (2915892).

Almost surely, 2^21623407 is an apocalyptic number.

21623407 is a deficient number, since it is larger than the sum of its proper divisors (1703729).

21623407 is a wasteful number, since it uses less digits than its factorization.

21623407 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2897.

The product of its (nonzero) digits is 2016, while the sum is 25.

The square root of 21623407 is about 4650.0975258590. The cubic root of 21623407 is about 278.5958915432.

The spelling of 21623407 in words is "twenty-one million, six hundred twenty-three thousand, four hundred seven".