21390519389 has 2 divisors, whose sum is σ = 21390519390. Its totient is φ = 21390519388.

The previous prime is 21390519347. The next prime is 21390519457. The reversal of 21390519389 is 98391509312.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17783556025 + 3606963364 = 133355^2 + 60058^2 .

It is a cyclic number.

It is not a de Polignac number, because 21390519389 - 2³² = 17095552093 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21390519329) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10695259694 + 10695259695.

It is an arithmetic number, because the mean of its divisors is an integer number (10695259695).

Almost surely, 2^21390519389 is an apocalyptic number.

It is an amenable number.

21390519389 is a deficient number, since it is larger than the sum of its proper divisors (1).

21390519389 is an equidigital number, since it uses as much as digits as its factorization.

21390519389 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 524880, while the sum is 50.

The spelling of 21390519389 in words is "twenty-one billion, three hundred ninety million, five hundred nineteen thousand, three hundred eighty-nine".