21435621149 has 2 divisors, whose sum is σ = 21435621150. Its totient is φ = 21435621148.

The previous prime is 21435621127. The next prime is 21435621157. The reversal of 21435621149 is 94112653412.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18835641049 + 2599980100 = 137243^2 + 50990^2 .

It is a cyclic number.

It is not a de Polignac number, because 21435621149 - 2²⁸ = 21167185693 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21435623149) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10717810574 + 10717810575.

It is an arithmetic number, because the mean of its divisors is an integer number (10717810575).

Almost surely, 2^21435621149 is an apocalyptic number.

It is an amenable number.

21435621149 is a deficient number, since it is larger than the sum of its proper divisors (1).

21435621149 is an equidigital number, since it uses as much as digits as its factorization.

21435621149 is an evil number, because the sum of its binary digits is even.

The product of its digits is 51840, while the sum is 38.

The spelling of 21435621149 in words is "twenty-one billion, four hundred thirty-five million, six hundred twenty-one thousand, one hundred forty-nine".