21150475757 has 8 divisors (see below), whose sum is σ = 21238113720. Its totient is φ = 21062926080.

The previous prime is 21150475711. The next prime is 21150475807. The reversal of 21150475757 is 75757405112.

It can be written as a sum of positive squares in 4 ways, for example, as 4006763401 + 17143712356 = 63299^2 + 130934^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21150475757 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 (21150475457) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 481673 + ... + 523745.

It is an arithmetic number, because the mean of its divisors is an integer number (2654764215).

Almost surely, 2^21150475757 is an apocalyptic number.

It is an amenable number.

21150475757 is a deficient number, since it is larger than the sum of its proper divisors (87637963).

21150475757 is a wasteful number, since it uses less digits than its factorization.

21150475757 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 44143.

The product of its (nonzero) digits is 343000, while the sum is 44.

The spelling of 21150475757 in words is "twenty-one billion, one hundred fifty million, four hundred seventy-five thousand, seven hundred fifty-seven".