21355907 has 8 divisors (see below), whose sum is σ = 22319616. Its totient is φ = 20413512.

The previous prime is 21355903. The next prime is 21355909. The reversal of 21355907 is 70955312.

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 21355907 - 2² = 21355903 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21355903) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3263 + ... + 7304.

It is an arithmetic number, because the mean of its divisors is an integer number (2789952).

Almost surely, 2^21355907 is an apocalyptic number.

21355907 is a deficient number, since it is larger than the sum of its proper divisors (963709).

21355907 is a wasteful number, since it uses less digits than its factorization.

21355907 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10657.

The product of its (nonzero) digits is 9450, while the sum is 32.

The square root of 21355907 is about 4621.2451785206. The cubic root of 21355907 is about 277.4422984213.

The spelling of 21355907 in words is "twenty-one million, three hundred fifty-five thousand, nine hundred seven".