21379355 has 4 divisors (see below), whose sum is σ = 25655232. Its totient is φ = 17103480.

The previous prime is 21379339. The next prime is 21379363. The reversal of 21379355 is 55397312.

It is a happy number.

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

It is not a de Polignac number, because 21379355 - 2⁴ = 21379339 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2137931 + ... + 2137940.

It is an arithmetic number, because the mean of its divisors is an integer number (6413808).

Almost surely, 2^21379355 is an apocalyptic number.

21379355 is a deficient number, since it is larger than the sum of its proper divisors (4275877).

21379355 is an equidigital number, since it uses as much as digits as its factorization.

21379355 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4275876.

The product of its digits is 28350, while the sum is 35.

The square root of 21379355 is about 4623.7814610987. The cubic root of 21379355 is about 277.5438017593.

The spelling of 21379355 in words is "twenty-one million, three hundred seventy-nine thousand, three hundred fifty-five".