21070739 has 2 divisors, whose sum is σ = 21070740. Its totient is φ = 21070738.

The previous prime is 21070727. The next prime is 21070747. The reversal of 21070739 is 93707012.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21070739 is a prime.

It is a super-2 number, since 2×21070739² = 887952084012242, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21070759) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10535369 + 10535370.

It is an arithmetic number, because the mean of its divisors is an integer number (10535370).

Almost surely, 2^21070739 is an apocalyptic number.

21070739 is a deficient number, since it is larger than the sum of its proper divisors (1).

21070739 is an equidigital number, since it uses as much as digits as its factorization.

21070739 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2646, while the sum is 29.

The square root of 21070739 is about 4590.2874637652. The cubic root of 21070739 is about 276.2018538426.

The spelling of 21070739 in words is "twenty-one million, seventy thousand, seven hundred thirty-nine".