21330157 has 2 divisors, whose sum is σ = 21330158. Its totient is φ = 21330156.

The previous prime is 21330149. The next prime is 21330161. The reversal of 21330157 is 75103312.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21215236 + 114921 = 4606^2 + 339^2 .

It is a cyclic number.

It is not a de Polignac number, because 21330157 - 2³ = 21330149 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21331157) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10665078 + 10665079.

It is an arithmetic number, because the mean of its divisors is an integer number (10665079).

Almost surely, 2^21330157 is an apocalyptic number.

It is an amenable number.

21330157 is a deficient number, since it is larger than the sum of its proper divisors (1).

21330157 is an equidigital number, since it uses as much as digits as its factorization.

21330157 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 630, while the sum is 22.

The square root of 21330157 is about 4618.4582925474. The cubic root of 21330157 is about 277.3307443913.

Adding to 21330157 its reverse (75103312), we get a palindrome (96433469).

The spelling of 21330157 in words is "twenty-one million, three hundred thirty thousand, one hundred fifty-seven".