21420754799 has 2 divisors, whose sum is σ = 21420754800. Its totient is φ = 21420754798.

The previous prime is 21420754787. The next prime is 21420754813. The reversal of 21420754799 is 99745702412.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21420754799 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21420754739) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10710377399 + 10710377400.

It is an arithmetic number, because the mean of its divisors is an integer number (10710377400).

Almost surely, 2^21420754799 is an apocalyptic number.

21420754799 is a deficient number, since it is larger than the sum of its proper divisors (1).

21420754799 is an equidigital number, since it uses as much as digits as its factorization.

21420754799 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1270080, while the sum is 50.

The spelling of 21420754799 in words is "twenty-one billion, four hundred twenty million, seven hundred fifty-four thousand, seven hundred ninety-nine".