21069387 has 12 divisors (see below), whose sum is σ = 30476784. Its totient is φ = 14026320.

The previous prime is 21069383. The next prime is 21069421. The reversal of 21069387 is 78396012.

21069387 is a `hidden beast` number, since 210 + 69 + 387 = 666.

It is not a de Polignac number, because 21069387 - 2² = 21069383 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21069383) 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 in 11 ways as a sum of consecutive naturals, for example, 7962 + ... + 10272.

It is an arithmetic number, because the mean of its divisors is an integer number (2539732).

Almost surely, 2^21069387 is an apocalyptic number.

21069387 is a deficient number, since it is larger than the sum of its proper divisors (9407397).

21069387 is a wasteful number, since it uses less digits than its factorization.

21069387 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3330 (or 3327 counting only the distinct ones).

The product of its (nonzero) digits is 18144, while the sum is 36.

The square root of 21069387 is about 4590.1401939374. The cubic root of 21069387 is about 276.1959462362.

The spelling of 21069387 in words is "twenty-one million, sixty-nine thousand, three hundred eighty-seven".