21743157 has 4 divisors (see below), whose sum is σ = 28990880. Its totient is φ = 14495436.

The previous prime is 21743131. The next prime is 21743177. The reversal of 21743157 is 75134712.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 21743157 - 2¹⁵ = 21710389 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 (21743107) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3623857 + ... + 3623862.

It is an arithmetic number, because the mean of its divisors is an integer number (7247720).

Almost surely, 2^21743157 is an apocalyptic number.

It is an amenable number.

21743157 is a deficient number, since it is larger than the sum of its proper divisors (7247723).

21743157 is an equidigital number, since it uses as much as digits as its factorization.

21743157 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7247722.

The product of its digits is 5880, while the sum is 30.

The square root of 21743157 is about 4662.9558222226. The cubic root of 21743157 is about 279.1092312623.

Adding to 21743157 its reverse (75134712), we get a palindrome (96877869).

The spelling of 21743157 in words is "twenty-one million, seven hundred forty-three thousand, one hundred fifty-seven".