21515332549 has 16 divisors (see below), whose sum is σ = 23043336192. Its totient is φ = 20017435648.

The previous prime is 21515332547. The next prime is 21515332561. The reversal of 21515332549 is 94523351512.

It is a cyclic number.

It is not a de Polignac number, because 21515332549 - 2¹ = 21515332547 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21515332547) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 721122 + ... + 750364.

It is an arithmetic number, because the mean of its divisors is an integer number (1440208512).

Almost surely, 2^21515332549 is an apocalyptic number.

It is an amenable number.

21515332549 is a deficient number, since it is larger than the sum of its proper divisors (1528003643).

21515332549 is a wasteful number, since it uses less digits than its factorization.

21515332549 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29756.

The product of its digits is 162000, while the sum is 40.

The spelling of 21515332549 in words is "twenty-one billion, five hundred fifteen million, three hundred thirty-two thousand, five hundred forty-nine".