21389719451 has 2 divisors, whose sum is σ = 21389719452. Its totient is φ = 21389719450.

The previous prime is 21389719409. The next prime is 21389719493. The reversal of 21389719451 is 15491798312.

It is a balanced prime because it is at equal distance from previous prime (21389719409) and next prime (21389719493).

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21389719451 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21389719451.

It is not a weakly prime, because it can be changed into another prime (21389719151) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10694859725 + 10694859726.

It is an arithmetic number, because the mean of its divisors is an integer number (10694859726).

Almost surely, 2^21389719451 is an apocalyptic number.

21389719451 is a deficient number, since it is larger than the sum of its proper divisors (1).

21389719451 is an equidigital number, since it uses as much as digits as its factorization.

21389719451 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 544320, while the sum is 50.

The spelling of 21389719451 in words is "twenty-one billion, three hundred eighty-nine million, seven hundred nineteen thousand, four hundred fifty-one".