21432746 has 4 divisors (see below), whose sum is σ = 32149122. Its totient is φ = 10716372.

The previous prime is 21432743. The next prime is 21432751. The reversal of 21432746 is 64723412.

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

It can be written as a sum of positive squares in only one way, i.e., 11122225 + 10310521 = 3335^2 + 3211^2 .

It is a super-2 number, since 2×21432746² = 918725202201032, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21432743) 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 as a sum of consecutive naturals, namely, 5358185 + ... + 5358188.

Almost surely, 2^21432746 is an apocalyptic number.

21432746 is a deficient number, since it is larger than the sum of its proper divisors (10716376).

21432746 is a wasteful number, since it uses less digits than its factorization.

21432746 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10716375.

The product of its digits is 8064, while the sum is 29.

The square root of 21432746 is about 4629.5513821536. The cubic root of 21432746 is about 277.7746478699.

The spelling of 21432746 in words is "twenty-one million, four hundred thirty-two thousand, seven hundred forty-six".