21139733 has 4 divisors (see below), whose sum is σ = 21486348. Its totient is φ = 20793120.

The previous prime is 21139717. The next prime is 21139747. The reversal of 21139733 is 33793112.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 6340324 + 14799409 = 2518^2 + 3847^2 .

It is a cyclic number.

It is not a de Polignac number, because 21139733 - 2⁴ = 21139717 is a prime.

It is a super-2 number, since 2×21139733² = 893776622622578, which contains 22 as substring.

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 = 21139696 and 21139705.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21139793) 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, 173216 + ... + 173337.

It is an arithmetic number, because the mean of its divisors is an integer number (5371587).

Almost surely, 2^21139733 is an apocalyptic number.

It is an amenable number.

21139733 is a deficient number, since it is larger than the sum of its proper divisors (346615).

21139733 is an equidigital number, since it uses as much as digits as its factorization.

21139733 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 346614.

The product of its digits is 3402, while the sum is 29.

The square root of 21139733 is about 4597.7965374731. The cubic root of 21139733 is about 276.5029903963.

The spelling of 21139733 in words is "twenty-one million, one hundred thirty-nine thousand, seven hundred thirty-three".