21069638 has 4 divisors (see below), whose sum is σ = 31604460. Its totient is φ = 10534818.

The previous prime is 21069637. The next prime is 21069649. The reversal of 21069638 is 83696012.

It is a semiprime because it is the product of two primes.

It is a junction number, because it is equal to n+sod(n) for n = 21069598 and 21069607.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21069637) 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 as a sum of consecutive naturals, namely, 5267408 + ... + 5267411.

It is an arithmetic number, because the mean of its divisors is an integer number (7901115).

Almost surely, 2^21069638 is an apocalyptic number.

21069638 is a deficient number, since it is larger than the sum of its proper divisors (10534822).

21069638 is a wasteful number, since it uses less digits than its factorization.

21069638 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10534821.

The product of its (nonzero) digits is 15552, while the sum is 35.

The square root of 21069638 is about 4590.1675350688. The cubic root of 21069638 is about 276.1970430077.

The spelling of 21069638 in words is "twenty-one million, sixty-nine thousand, six hundred thirty-eight".