19764139 has 2 divisors, whose sum is σ = 19764140. Its totient is φ = 19764138.

The previous prime is 19764137. The next prime is 19764163. The reversal of 19764139 is 93146791.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 19764139 - 2¹ = 19764137 is a prime.

It is a super-2 number, since 2×19764139² = 781242380822642, which contains 22 as substring.

Together with 19764137, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (19764131) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9882069 + 9882070.

It is an arithmetic number, because the mean of its divisors is an integer number (9882070).

Almost surely, 2^19764139 is an apocalyptic number.

19764139 is a deficient number, since it is larger than the sum of its proper divisors (1).

19764139 is an equidigital number, since it uses as much as digits as its factorization.

19764139 is an evil number, because the sum of its binary digits is even.

The product of its digits is 40824, while the sum is 40.

The square root of 19764139 is about 4445.6876858367. The cubic root of 19764139 is about 270.3704973107.

The spelling of 19764139 in words is "nineteen million, seven hundred sixty-four thousand, one hundred thirty-nine".