21247132 has 6 divisors (see below), whose sum is σ = 37182488. Its totient is φ = 10623564.

The previous prime is 21247103. The next prime is 21247133. The reversal of 21247132 is 23174212.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21247133) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2655888 + ... + 2655895.

Almost surely, 2^21247132 is an apocalyptic number.

It is an amenable number.

21247132 is a deficient number, since it is larger than the sum of its proper divisors (15935356).

21247132 is a wasteful number, since it uses less digits than its factorization.

21247132 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5311787 (or 5311785 counting only the distinct ones).

The product of its digits is 672, while the sum is 22.

The square root of 21247132 is about 4609.4611398731. The cubic root of 21247132 is about 276.9704513046.

The spelling of 21247132 in words is "twenty-one million, two hundred forty-seven thousand, one hundred thirty-two".