21355001 has 4 divisors (see below), whose sum is σ = 22043904. Its totient is φ = 20666100.

The previous prime is 21354989. The next prime is 21355003. The reversal of 21355001 is 10055312.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21355001 - 2¹⁰ = 21353977 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21355003) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 344405 + ... + 344466.

It is an arithmetic number, because the mean of its divisors is an integer number (5510976).

Almost surely, 2^21355001 is an apocalyptic number.

It is an amenable number.

21355001 is a deficient number, since it is larger than the sum of its proper divisors (688903).

21355001 is an equidigital number, since it uses as much as digits as its factorization.

21355001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 688902.

The product of its (nonzero) digits is 150, while the sum is 17.

The square root of 21355001 is about 4621.1471519526. The cubic root of 21355001 is about 277.4383749747.

The spelling of 21355001 in words is "twenty-one million, three hundred fifty-five thousand, one".