21139706 has 32 divisors (see below), whose sum is σ = 38019072. Its totient is φ = 8624880.

The previous prime is 21139667. The next prime is 21139709. The reversal of 21139706 is 60793112.

It is not an unprimeable number, because it can be changed into a prime (21139709) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 28715 + ... + 29441.

It is an arithmetic number, because the mean of its divisors is an integer number (1188096).

Almost surely, 2^21139706 is an apocalyptic number.

21139706 is a deficient number, since it is larger than the sum of its proper divisors (16879366).

21139706 is a wasteful number, since it uses less digits than its factorization.

21139706 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 834.

The product of its (nonzero) digits is 2268, while the sum is 29.

The square root of 21139706 is about 4597.7936012831. The cubic root of 21139706 is about 276.5028726783.

The spelling of 21139706 in words is "twenty-one million, one hundred thirty-nine thousand, seven hundred six".