21682357 has 2 divisors, whose sum is σ = 21682358. Its totient is φ = 21682356.

The previous prime is 21682337. The next prime is 21682379. The reversal of 21682357 is 75328612.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21446161 + 236196 = 4631^2 + 486^2 .

It is a cyclic number.

It is not a de Polignac number, because 21682357 - 2⁷ = 21682229 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21682337) 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, 10841178 + 10841179.

It is an arithmetic number, because the mean of its divisors is an integer number (10841179).

Almost surely, 2^21682357 is an apocalyptic number.

It is an amenable number.

21682357 is a deficient number, since it is larger than the sum of its proper divisors (1).

21682357 is an equidigital number, since it uses as much as digits as its factorization.

21682357 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 20160, while the sum is 34.

The square root of 21682357 is about 4656.4317883976. The cubic root of 21682357 is about 278.8488323489.

The spelling of 21682357 in words is "twenty-one million, six hundred eighty-two thousand, three hundred fifty-seven".