21853487 has 2 divisors, whose sum is σ = 21853488. Its totient is φ = 21853486.

The previous prime is 21853399. The next prime is 21853493. The reversal of 21853487 is 78435812.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21853487 - 2⁸ = 21853231 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21853487.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21853387) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10926743 + 10926744.

It is an arithmetic number, because the mean of its divisors is an integer number (10926744).

Almost surely, 2^21853487 is an apocalyptic number.

21853487 is a deficient number, since it is larger than the sum of its proper divisors (1).

21853487 is an equidigital number, since it uses as much as digits as its factorization.

21853487 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 53760, while the sum is 38.

The square root of 21853487 is about 4674.7713313059. The cubic root of 21853487 is about 279.5805240960.

The spelling of 21853487 in words is "twenty-one million, eight hundred fifty-three thousand, four hundred eighty-seven".