21072443757 has 16 divisors (see below), whose sum is σ = 28384527360. Its totient is φ = 13904424000.

The previous prime is 21072443747. The next prime is 21072443803. The reversal of 21072443757 is 75734427012.

It is not a de Polignac number, because 21072443757 - 2⁴ = 21072443741 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21072443747) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1017219 + ... + 1037727.

It is an arithmetic number, because the mean of its divisors is an integer number (1774032960).

Almost surely, 2^21072443757 is an apocalyptic number.

It is an amenable number.

21072443757 is a deficient number, since it is larger than the sum of its proper divisors (7312083603).

21072443757 is a wasteful number, since it uses less digits than its factorization.

21072443757 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24004.

The product of its (nonzero) digits is 329280, while the sum is 42.

The spelling of 21072443757 in words is "twenty-one billion, seventy-two million, four hundred forty-three thousand, seven hundred fifty-seven".