21239054387 has 2 divisors, whose sum is σ = 21239054388. Its totient is φ = 21239054386.

The previous prime is 21239054383. The next prime is 21239054503. The reversal of 21239054387 is 78345093212.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21239054387 - 2² = 21239054383 is a prime.

It is not a weakly prime, because it can be changed into another prime (21239054383) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10619527193 + 10619527194.

It is an arithmetic number, because the mean of its divisors is an integer number (10619527194).

Almost surely, 2^21239054387 is an apocalyptic number.

21239054387 is a deficient number, since it is larger than the sum of its proper divisors (1).

21239054387 is an equidigital number, since it uses as much as digits as its factorization.

21239054387 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 362880, while the sum is 44.

The spelling of 21239054387 in words is "twenty-one billion, two hundred thirty-nine million, fifty-four thousand, three hundred eighty-seven".