21307642 has 8 divisors (see below), whose sum is σ = 32066496. Its totient is φ = 10618812.

The previous prime is 21307609. The next prime is 21307669. The reversal of 21307642 is 24670312.

It is a sphenic number, since it is the product of 3 distinct primes.

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 3 ways as a sum of consecutive naturals, for example, 16738 + ... + 17965.

It is an arithmetic number, because the mean of its divisors is an integer number (4008312).

Almost surely, 2^21307642 is an apocalyptic number.

21307642 is a deficient number, since it is larger than the sum of its proper divisors (10758854).

21307642 is a wasteful number, since it uses less digits than its factorization.

21307642 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 35012.

The product of its (nonzero) digits is 2016, while the sum is 25.

The square root of 21307642 is about 4616.0201472697. The cubic root of 21307642 is about 277.2331314204.

Adding to 21307642 its reverse (24670312), we get a palindrome (45977954).

The spelling of 21307642 in words is "twenty-one million, three hundred seven thousand, six hundred forty-two".