21351901 has 16 divisors (see below), whose sum is σ = 22809600. Its totient is φ = 19958400.

The previous prime is 21351899. The next prime is 21351907. The reversal of 21351901 is 10915312.

It is a cyclic number.

It is not a de Polignac number, because 21351901 - 2¹ = 21351899 is a prime.

It is a Duffinian number.

It is a plaindrome in base 16.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21351907) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 195835 + ... + 195943.

It is an arithmetic number, because the mean of its divisors is an integer number (1425600).

Almost surely, 2^21351901 is an apocalyptic number.

It is an amenable number.

21351901 is a deficient number, since it is larger than the sum of its proper divisors (1457699).

21351901 is a wasteful number, since it uses less digits than its factorization.

21351901 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 300.

The product of its (nonzero) digits is 270, while the sum is 22.

The square root of 21351901 is about 4620.8117252275. The cubic root of 21351901 is about 277.4249495390.

The spelling of 21351901 in words is "twenty-one million, three hundred fifty-one thousand, nine hundred one".