21139069 has 4 divisors (see below), whose sum is σ = 24158944. Its totient is φ = 18119196.

The previous prime is 21139061. The next prime is 21139087. The reversal of 21139069 is 96093112.

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 not a de Polignac number, because 21139069 - 2³ = 21139061 is a prime.

It is a super-2 number, since 2×21139069² = 893720476373522, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21139069.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21139061) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1509927 + ... + 1509940.

It is an arithmetic number, because the mean of its divisors is an integer number (6039736).

Almost surely, 2^21139069 is an apocalyptic number.

It is an amenable number.

21139069 is a deficient number, since it is larger than the sum of its proper divisors (3019875).

21139069 is an equidigital number, since it uses as much as digits as its factorization.

21139069 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3019874.

The product of its (nonzero) digits is 2916, while the sum is 31.

The square root of 21139069 is about 4597.7243284042. The cubic root of 21139069 is about 276.5000953754.

The spelling of 21139069 in words is "twenty-one million, one hundred thirty-nine thousand, sixty-nine".