21185361739 has 2 divisors, whose sum is σ = 21185361740. Its totient is φ = 21185361738.

The previous prime is 21185361737. The next prime is 21185361761. The reversal of 21185361739 is 93716358112.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21185361739 - 2¹ = 21185361737 is a prime.

Together with 21185361737, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (21185361731) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10592680869 + 10592680870.

It is an arithmetic number, because the mean of its divisors is an integer number (10592680870).

Almost surely, 2^21185361739 is an apocalyptic number.

21185361739 is a deficient number, since it is larger than the sum of its proper divisors (1).

21185361739 is an equidigital number, since it uses as much as digits as its factorization.

21185361739 is an evil number, because the sum of its binary digits is even.

The product of its digits is 272160, while the sum is 46.

The spelling of 21185361739 in words is "twenty-one billion, one hundred eighty-five million, three hundred sixty-one thousand, seven hundred thirty-nine".