21329642 has 4 divisors (see below), whose sum is σ = 31994466. Its totient is φ = 10664820.

The previous prime is 21329641. The next prime is 21329663. The reversal of 21329642 is 24692312.

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., 13980121 + 7349521 = 3739^2 + 2711^2 .

It is not an unprimeable number, because it can be changed into a prime (21329641) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5332409 + ... + 5332412.

Almost surely, 2^21329642 is an apocalyptic number.

21329642 is a deficient number, since it is larger than the sum of its proper divisors (10664824).

21329642 is a wasteful number, since it uses less digits than its factorization.

21329642 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10664823.

The product of its digits is 5184, while the sum is 29.

The square root of 21329642 is about 4618.4025376747. The cubic root of 21329642 is about 277.3285123951.

The spelling of 21329642 in words is "twenty-one million, three hundred twenty-nine thousand, six hundred forty-two".