21682487 has 2 divisors, whose sum is σ = 21682488. Its totient is φ = 21682486.

The previous prime is 21682433. The next prime is 21682499. The reversal of 21682487 is 78428612.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21682487 - 2⁸ = 21682231 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 21682487.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21682417) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10841243 + 10841244.

It is an arithmetic number, because the mean of its divisors is an integer number (10841244).

Almost surely, 2^21682487 is an apocalyptic number.

21682487 is a deficient number, since it is larger than the sum of its proper divisors (1).

21682487 is an equidigital number, since it uses as much as digits as its factorization.

21682487 is an evil number, because the sum of its binary digits is even.

The product of its digits is 43008, while the sum is 38.

The square root of 21682487 is about 4656.4457475633. The cubic root of 21682487 is about 278.8493896419.

The spelling of 21682487 in words is "twenty-one million, six hundred eighty-two thousand, four hundred eighty-seven".