21421733 has 4 divisors (see below), whose sum is σ = 21456960. Its totient is φ = 21386508.

The previous prime is 21421727. The next prime is 21421747. The reversal of 21421733 is 33712412.

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 a de Polignac number, because none of the positive numbers 2^k-21421733 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21421699 and 21421708.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21421703) 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, 16685 + ... + 17922.

It is an arithmetic number, because the mean of its divisors is an integer number (5364240).

Almost surely, 2^21421733 is an apocalyptic number.

It is an amenable number.

21421733 is a deficient number, since it is larger than the sum of its proper divisors (35227).

21421733 is an equidigital number, since it uses as much as digits as its factorization.

21421733 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 35226.

The product of its digits is 1008, while the sum is 23.

The square root of 21421733 is about 4628.3618052179. The cubic root of 21421733 is about 277.7270624864.

The spelling of 21421733 in words is "twenty-one million, four hundred twenty-one thousand, seven hundred thirty-three".