21142706 has 32 divisors (see below), whose sum is σ = 36341760. Its totient is φ = 9144576.

The previous prime is 21142699. The next prime is 21142729. The reversal of 21142706 is 60724112.

It is an unprimeable number.

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, 62570 + ... + 62906.

It is an arithmetic number, because the mean of its divisors is an integer number (1135680).

Almost surely, 2^21142706 is an apocalyptic number.

21142706 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

21142706 is a deficient number, since it is larger than the sum of its proper divisors (15199054).

21142706 is a wasteful number, since it uses less digits than its factorization.

21142706 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 498.

The product of its (nonzero) digits is 672, while the sum is 23.

The square root of 21142706 is about 4598.1198331492. The cubic root of 21142706 is about 276.5159518476.

Adding to 21142706 its reverse (60724112), we get a palindrome (81866818).

The spelling of 21142706 in words is "twenty-one million, one hundred forty-two thousand, seven hundred six".