21451439629 has 2 divisors, whose sum is σ = 21451439630. Its totient is φ = 21451439628.

The previous prime is 21451439617. The next prime is 21451439671. The reversal of 21451439629 is 92693415412.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21161520900 + 289918729 = 145470^2 + 17027^2 .

It is a cyclic number.

It is not a de Polignac number, because 21451439629 - 2¹³ = 21451431437 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21451439329) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10725719814 + 10725719815.

It is an arithmetic number, because the mean of its divisors is an integer number (10725719815).

Almost surely, 2^21451439629 is an apocalyptic number.

It is an amenable number.

21451439629 is a deficient number, since it is larger than the sum of its proper divisors (1).

21451439629 is an equidigital number, since it uses as much as digits as its factorization.

21451439629 is an evil number, because the sum of its binary digits is even.

The product of its digits is 466560, while the sum is 46.

The spelling of 21451439629 in words is "twenty-one billion, four hundred fifty-one million, four hundred thirty-nine thousand, six hundred twenty-nine".