21986351 has 2 divisors, whose sum is σ = 21986352. Its totient is φ = 21986350.

The previous prime is 21986333. The next prime is 21986369. The reversal of 21986351 is 15368912.

It is a balanced prime because it is at equal distance from previous prime (21986333) and next prime (21986369).

It is a cyclic number.

It is not a de Polignac number, because 21986351 - 2¹⁸ = 21724207 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21986851) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10993175 + 10993176.

It is an arithmetic number, because the mean of its divisors is an integer number (10993176).

Almost surely, 2^21986351 is an apocalyptic number.

21986351 is a deficient number, since it is larger than the sum of its proper divisors (1).

21986351 is an equidigital number, since it uses as much as digits as its factorization.

21986351 is an evil number, because the sum of its binary digits is even.

The product of its digits is 12960, while the sum is 35.

The square root of 21986351 is about 4688.9605457926. The cubic root of 21986351 is about 280.1459740553.

The spelling of 21986351 in words is "twenty-one million, nine hundred eighty-six thousand, three hundred fifty-one".