21513329 has 2 divisors, whose sum is σ = 21513330. Its totient is φ = 21513328.

The previous prime is 21513307. The next prime is 21513361. The reversal of 21513329 is 92331512.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18905104 + 2608225 = 4348^2 + 1615^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21513329 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21513298 and 21513307.

It is not a weakly prime, because it can be changed into another prime (21513929) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10756664 + 10756665.

It is an arithmetic number, because the mean of its divisors is an integer number (10756665).

Almost surely, 2^21513329 is an apocalyptic number.

It is an amenable number.

21513329 is a deficient number, since it is larger than the sum of its proper divisors (1).

21513329 is an equidigital number, since it uses as much as digits as its factorization.

21513329 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1620, while the sum is 26.

The square root of 21513329 is about 4638.2463280856. The cubic root of 21513329 is about 278.1223388880.

The spelling of 21513329 in words is "twenty-one million, five hundred thirteen thousand, three hundred twenty-nine".