21910157 has 2 divisors, whose sum is σ = 21910158. Its totient is φ = 21910156.

The previous prime is 21910123. The next prime is 21910159. The reversal of 21910157 is 75101912.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21353641 + 556516 = 4621^2 + 746^2 .

It is a cyclic number.

It is not a de Polignac number, because 21910157 - 2¹² = 21906061 is a prime.

Together with 21910159, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21910159) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10955078 + 10955079.

It is an arithmetic number, because the mean of its divisors is an integer number (10955079).

Almost surely, 2^21910157 is an apocalyptic number.

It is an amenable number.

21910157 is a deficient number, since it is larger than the sum of its proper divisors (1).

21910157 is an equidigital number, since it uses as much as digits as its factorization.

21910157 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 26.

The square root of 21910157 is about 4680.8286659522. The cubic root of 21910157 is about 279.8219829336.

The spelling of 21910157 in words is "twenty-one million, nine hundred ten thousand, one hundred fifty-seven".