21501742 has 8 divisors (see below), whose sum is σ = 32272416. Its totient is φ = 10744272.

The previous prime is 21501737. The next prime is 21501811. The reversal of 21501742 is 24710512.

It is a happy number.

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

It is a congruent number.

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, 4018 + ... + 7690.

It is an arithmetic number, because the mean of its divisors is an integer number (4034052).

Almost surely, 2^21501742 is an apocalyptic number.

21501742 is a deficient number, since it is larger than the sum of its proper divisors (10770674).

21501742 is a wasteful number, since it uses less digits than its factorization.

21501742 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6602.

The product of its (nonzero) digits is 560, while the sum is 22.

The square root of 21501742 is about 4636.9970886340. The cubic root of 21501742 is about 278.0723980308.

The spelling of 21501742 in words is "twenty-one million, five hundred one thousand, seven hundred forty-two".