21142672 has 10 divisors (see below), whose sum is σ = 40963958. Its totient is φ = 10571328.

The previous prime is 21142669. The next prime is 21142699. The reversal of 21142672 is 27624112.

It can be written as a sum of positive squares in only one way, i.e., 11182336 + 9960336 = 3344^2 + 3156^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 660693 + ... + 660724.

Almost surely, 2^21142672 is an apocalyptic number.

It is an amenable number.

21142672 is a deficient number, since it is larger than the sum of its proper divisors (19821286).

21142672 is a wasteful number, since it uses less digits than its factorization.

21142672 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1321425 (or 1321419 counting only the distinct ones).

The product of its digits is 1344, while the sum is 25.

The square root of 21142672 is about 4598.1161359844. The cubic root of 21142672 is about 276.5158036239.

Adding to 21142672 its reverse (27624112), we get a palindrome (48766784).

The spelling of 21142672 in words is "twenty-one million, one hundred forty-two thousand, six hundred seventy-two".