21100357 has 2 divisors, whose sum is σ = 21100358. Its totient is φ = 21100356.

The previous prime is 21100351. The next prime is 21100379. The reversal of 21100357 is 75300112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20016676 + 1083681 = 4474^2 + 1041^2 .

It is a cyclic number.

It is not a de Polignac number, because 21100357 - 2²³ = 12711749 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21100351) 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 as a sum of consecutive naturals, namely, 10550178 + 10550179.

It is an arithmetic number, because the mean of its divisors is an integer number (10550179).

Almost surely, 2^21100357 is an apocalyptic number.

It is an amenable number.

21100357 is a deficient number, since it is larger than the sum of its proper divisors (1).

21100357 is an equidigital number, since it uses as much as digits as its factorization.

21100357 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 210, while the sum is 19.

The square root of 21100357 is about 4593.5124904587. The cubic root of 21100357 is about 276.3312072635.

Adding to 21100357 its reverse (75300112), we get a palindrome (96400469).

The spelling of 21100357 in words is "twenty-one million, one hundred thousand, three hundred fifty-seven".