21474139 has 2 divisors, whose sum is σ = 21474140. Its totient is φ = 21474138.

The previous prime is 21474137. The next prime is 21474143. The reversal of 21474139 is 93147412.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21474139 - 2¹ = 21474137 is a prime.

It is a super-2 number, since 2×21474139² = 922277291582642, which contains 22 as substring.

Together with 21474137, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 21474139.

It is not a weakly prime, because it can be changed into another prime (21474133) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10737069 + 10737070.

It is an arithmetic number, because the mean of its divisors is an integer number (10737070).

Almost surely, 2^21474139 is an apocalyptic number.

21474139 is a deficient number, since it is larger than the sum of its proper divisors (1).

21474139 is an equidigital number, since it uses as much as digits as its factorization.

21474139 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 6048, while the sum is 31.

The square root of 21474139 is about 4634.0197453183. The cubic root of 21474139 is about 277.9533546637.

The spelling of 21474139 in words is "twenty-one million, four hundred seventy-four thousand, one hundred thirty-nine".