21249628615 has 4 divisors (see below), whose sum is σ = 25499554344. Its totient is φ = 16999702888.

The previous prime is 21249628613. The next prime is 21249628649. The reversal of 21249628615 is 51682694212.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21249628615 - 2¹ = 21249628613 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 (21249628613) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2124962857 + ... + 2124962866.

It is an arithmetic number, because the mean of its divisors is an integer number (6374888586).

Almost surely, 2^21249628615 is an apocalyptic number.

21249628615 is a deficient number, since it is larger than the sum of its proper divisors (4249925729).

21249628615 is an equidigital number, since it uses as much as digits as its factorization.

21249628615 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4249925728.

The product of its digits is 414720, while the sum is 46.

The spelling of 21249628615 in words is "twenty-one billion, two hundred forty-nine million, six hundred twenty-eight thousand, six hundred fifteen".