21402432439 has 2 divisors, whose sum is σ = 21402432440. Its totient is φ = 21402432438.

The previous prime is 21402432391. The next prime is 21402432461. The reversal of 21402432439 is 93423420412.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21402432439 - 2¹⁷ = 21402301367 is a prime.

It is a super-2 number, since 2×21402432439² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21402432479) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10701216219 + 10701216220.

It is an arithmetic number, because the mean of its divisors is an integer number (10701216220).

Almost surely, 2^21402432439 is an apocalyptic number.

21402432439 is a deficient number, since it is larger than the sum of its proper divisors (1).

21402432439 is an equidigital number, since it uses as much as digits as its factorization.

21402432439 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 41472, while the sum is 34.

The spelling of 21402432439 in words is "twenty-one billion, four hundred two million, four hundred thirty-two thousand, four hundred thirty-nine".