21157117301 has 4 divisors (see below), whose sum is σ = 21886673100. Its totient is φ = 20427561504.

The previous prime is 21157117279. The next prime is 21157117337. The reversal of 21157117301 is 10371175112.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 8873828401 + 12283288900 = 94201^2 + 110830^2 .

It is a cyclic number.

It is not a de Polignac number, because 21157117301 - 2¹⁸ = 21156855157 is a prime.

It is a super-2 number, since 2×21157117301² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (29), and also a Moran number because the ratio is a prime number: 729555769 = 21157117301 / (2 + 1 + 1 + 5 + 7 + 1 + 1 + 7 + 3 + 0 + 1).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21157117391) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 364777856 + ... + 364777913.

It is an arithmetic number, because the mean of its divisors is an integer number (5471668275).

Almost surely, 2^21157117301 is an apocalyptic number.

It is an amenable number.

21157117301 is a deficient number, since it is larger than the sum of its proper divisors (729555799).

21157117301 is an equidigital number, since it uses as much as digits as its factorization.

21157117301 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 729555798.

The product of its (nonzero) digits is 1470, while the sum is 29.

The spelling of 21157117301 in words is "twenty-one billion, one hundred fifty-seven million, one hundred seventeen thousand, three hundred one".