21175719747 has 16 divisors (see below), whose sum is σ = 34749899520. Its totient is φ = 11169610272.

The previous prime is 21175719731. The next prime is 21175719749. The reversal of 21175719747 is 74791757112.

It is not a de Polignac number, because 21175719747 - 2⁴ = 21175719731 is a prime.

It is a super-2 number, since 2×21175719747² (a number of 21 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21175719747.

It is not an unprimeable number, because it can be changed into a prime (21175719749) 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, 38783097 + ... + 38783642.

It is an arithmetic number, because the mean of its divisors is an integer number (2171868720).

Almost surely, 2^21175719747 is an apocalyptic number.

21175719747 is a deficient number, since it is larger than the sum of its proper divisors (13574179773).

21175719747 is a wasteful number, since it uses less digits than its factorization.

21175719747 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 77566762.

The product of its digits is 864360, while the sum is 51.

The spelling of 21175719747 in words is "twenty-one billion, one hundred seventy-five million, seven hundred nineteen thousand, seven hundred forty-seven".