21748051499 has 4 divisors (see below), whose sum is σ = 23027348664. Its totient is φ = 20468754336.

The previous prime is 21748051471. The next prime is 21748051517. The reversal of 21748051499 is 99415084712.

It is a happy number.

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 21748051499 - 2⁸ = 21748051243 is a prime.

It is a super-2 number, since 2×21748051499² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21748051459) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 639648557 + ... + 639648590.

It is an arithmetic number, because the mean of its divisors is an integer number (5756837166).

Almost surely, 2^21748051499 is an apocalyptic number.

21748051499 is a deficient number, since it is larger than the sum of its proper divisors (1279297165).

21748051499 is a wasteful number, since it uses less digits than its factorization.

21748051499 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1279297164.

The product of its (nonzero) digits is 725760, while the sum is 50.

The spelling of 21748051499 in words is "twenty-one billion, seven hundred forty-eight million, fifty-one thousand, four hundred ninety-nine".