21548718849 has 48 divisors (see below), whose sum is σ = 35063938688. Its totient is φ = 11528552448.

The previous prime is 21548718799. The next prime is 21548718899. The reversal of 21548718849 is 94881784512.

It is an interprime number because it is at equal distance from previous prime (21548718799) and next prime (21548718899).

It is not a de Polignac number, because 21548718849 - 2¹² = 21548714753 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21548718899) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1162119 + ... + 1180515.

Almost surely, 2^21548718849 is an apocalyptic number.

It is an amenable number.

21548718849 is a deficient number, since it is larger than the sum of its proper divisors (13515219839).

21548718849 is a wasteful number, since it uses less digits than its factorization.

21548718849 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18634 (or 18617 counting only the distinct ones).

The product of its digits is 5160960, while the sum is 57.

The spelling of 21548718849 in words is "twenty-one billion, five hundred forty-eight million, seven hundred eighteen thousand, eight hundred forty-nine".