21692287 has 2 divisors, whose sum is σ = 21692288. Its totient is φ = 21692286.

The previous prime is 21692273. The next prime is 21692291. The reversal of 21692287 is 78229612.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21692287 - 2¹¹ = 21690239 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21692267) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10846143 + 10846144.

It is an arithmetic number, because the mean of its divisors is an integer number (10846144).

Almost surely, 2^21692287 is an apocalyptic number.

21692287 is a deficient number, since it is larger than the sum of its proper divisors (1).

21692287 is an equidigital number, since it uses as much as digits as its factorization.

21692287 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 24192, while the sum is 37.

The square root of 21692287 is about 4657.4979334402. The cubic root of 21692287 is about 278.8913945468.

The spelling of 21692287 in words is "twenty-one million, six hundred ninety-two thousand, two hundred eighty-seven".