21231807 has 8 divisors (see below), whose sum is σ = 29222400. Its totient is φ = 13697880.

The previous prime is 21231787. The next prime is 21231811. The reversal of 21231807 is 70813212.

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

It is not a de Polignac number, because 21231807 - 2¹² = 21227711 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21231877) 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, 114057 + ... + 114242.

It is an arithmetic number, because the mean of its divisors is an integer number (3652800).

Almost surely, 2^21231807 is an apocalyptic number.

21231807 is a deficient number, since it is larger than the sum of its proper divisors (7990593).

21231807 is a wasteful number, since it uses less digits than its factorization.

21231807 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 228333.

The product of its (nonzero) digits is 672, while the sum is 24.

The square root of 21231807 is about 4607.7984981985. The cubic root of 21231807 is about 276.9038447767.

The spelling of 21231807 in words is "twenty-one million, two hundred thirty-one thousand, eight hundred seven".