21236901 has 8 divisors (see below), whose sum is σ = 32361024. Its totient is φ = 12135360.

The previous prime is 21236899. The next prime is 21236909. The reversal of 21236901 is 10963212.

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

It is not a de Polignac number, because 21236901 - 2¹ = 21236899 is a prime.

It is a Smith number, since the sum of its digits (24) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is an alternating number because its digits alternate between even and odd.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21236909) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 505620 + ... + 505661.

It is an arithmetic number, because the mean of its divisors is an integer number (4045128).

Almost surely, 2^21236901 is an apocalyptic number.

21236901 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

21236901 is a deficient number, since it is larger than the sum of its proper divisors (11124123).

21236901 is a wasteful number, since it uses less digits than its factorization.

21236901 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1011291.

The product of its (nonzero) digits is 648, while the sum is 24.

The square root of 21236901 is about 4608.3512235940. The cubic root of 21236901 is about 276.9259882113.

The spelling of 21236901 in words is "twenty-one million, two hundred thirty-six thousand, nine hundred one".