21439355 has 8 divisors (see below), whose sum is σ = 29402592. Its totient is φ = 14701248.

The previous prime is 21439343. The next prime is 21439387. The reversal of 21439355 is 55393412.

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 21439355 - 2⁶ = 21439291 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 306242 + ... + 306311.

It is an arithmetic number, because the mean of its divisors is an integer number (3675324).

Almost surely, 2^21439355 is an apocalyptic number.

21439355 is a deficient number, since it is larger than the sum of its proper divisors (7963237).

21439355 is an equidigital number, since it uses as much as digits as its factorization.

21439355 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 612565.

The product of its digits is 16200, while the sum is 32.

The square root of 21439355 is about 4630.2651112004. The cubic root of 21439355 is about 277.8031964591.

The spelling of 21439355 in words is "twenty-one million, four hundred thirty-nine thousand, three hundred fifty-five".