21920307 has 8 divisors (see below), whose sum is σ = 29259984. Its totient is φ = 14597088.

The previous prime is 21920299. The next prime is 21920321. The reversal of 21920307 is 70302912.

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

It is not a de Polignac number, because 21920307 - 2³ = 21920299 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21925307) 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, 568 + ... + 6645.

It is an arithmetic number, because the mean of its divisors is an integer number (3657498).

Almost surely, 2^21920307 is an apocalyptic number.

21920307 is a deficient number, since it is larger than the sum of its proper divisors (7339677).

21920307 is a wasteful number, since it uses less digits than its factorization.

21920307 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8229.

The product of its (nonzero) digits is 756, while the sum is 24.

The square root of 21920307 is about 4681.9127501482. The cubic root of 21920307 is about 279.8651859507.

The spelling of 21920307 in words is "twenty-one million, nine hundred twenty thousand, three hundred seven".