21309801 has 8 divisors (see below), whose sum is σ = 28879104. Its totient is φ = 13973520.

The previous prime is 21309793. The next prime is 21309829. The reversal of 21309801 is 10890312.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21309801 - 2³ = 21309793 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21309401) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 58041 + ... + 58406.

It is an arithmetic number, because the mean of its divisors is an integer number (3609888).

Almost surely, 2^21309801 is an apocalyptic number.

It is an amenable number.

21309801 is a deficient number, since it is larger than the sum of its proper divisors (7569303).

21309801 is a wasteful number, since it uses less digits than its factorization.

21309801 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 116511.

The product of its (nonzero) digits is 432, while the sum is 24.

The square root of 21309801 is about 4616.2540008106. The cubic root of 21309801 is about 277.2424946669.

The spelling of 21309801 in words is "twenty-one million, three hundred nine thousand, eight hundred one".