21545742 has 8 divisors (see below), whose sum is σ = 43091496. Its totient is φ = 7181912.

The previous prime is 21545723. The next prime is 21545759. The reversal of 21545742 is 24754512.

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

21545742 is an admirable number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1795473 + ... + 1795484.

It is an arithmetic number, because the mean of its divisors is an integer number (5386437).

Almost surely, 2^21545742 is an apocalyptic number.

21545742 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21545742 is a wasteful number, since it uses less digits than its factorization.

21545742 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3590962.

The product of its digits is 11200, while the sum is 30.

The square root of 21545742 is about 4641.7391137374. The cubic root of 21545742 is about 278.2619462262.

The spelling of 21545742 in words is "twenty-one million, five hundred forty-five thousand, seven hundred forty-two".