21874157 has 2 divisors, whose sum is σ = 21874158. Its totient is φ = 21874156.

The previous prime is 21874147. The next prime is 21874163. The reversal of 21874157 is 75147812.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17147881 + 4726276 = 4141^2 + 2174^2 .

It is a cyclic number.

It is not a de Polignac number, because 21874157 - 2¹⁶ = 21808621 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 (21874147) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10937078 + 10937079.

It is an arithmetic number, because the mean of its divisors is an integer number (10937079).

Almost surely, 2^21874157 is an apocalyptic number.

It is an amenable number.

21874157 is a deficient number, since it is larger than the sum of its proper divisors (1).

21874157 is an equidigital number, since it uses as much as digits as its factorization.

21874157 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 15680, while the sum is 35.

The square root of 21874157 is about 4676.9816121084. The cubic root of 21874157 is about 279.6686428846.

The spelling of 21874157 in words is "twenty-one million, eight hundred seventy-four thousand, one hundred fifty-seven".