21375739 has 12 divisors (see below), whose sum is σ = 26853232. Its totient is φ = 16655760.

The previous prime is 21375721. The next prime is 21375743. The reversal of 21375739 is 93757312.

It is not a de Polignac number, because 21375739 - 2⁷ = 21375611 is a prime.

It is a super-2 number, since 2×21375739² = 913844435592242, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21375698 and 21375707.

It is not an unprimeable number, because it can be changed into a prime (21375799) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 11772 + ... + 13465.

Almost surely, 2^21375739 is an apocalyptic number.

21375739 is a deficient number, since it is larger than the sum of its proper divisors (5477493).

21375739 is a wasteful number, since it uses less digits than its factorization.

21375739 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25266 (or 25255 counting only the distinct ones).

The product of its digits is 39690, while the sum is 37.

The square root of 21375739 is about 4623.3904226228. The cubic root of 21375739 is about 277.5281534080.

The spelling of 21375739 in words is "twenty-one million, three hundred seventy-five thousand, seven hundred thirty-nine".