21577742 has 4 divisors (see below), whose sum is σ = 32366616. Its totient is φ = 10788870.

The previous prime is 21577739. The next prime is 21577753. The reversal of 21577742 is 24777512.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5394434 + ... + 5394437.

It is an arithmetic number, because the mean of its divisors is an integer number (8091654).

Almost surely, 2^21577742 is an apocalyptic number.

21577742 is a deficient number, since it is larger than the sum of its proper divisors (10788874).

21577742 is a wasteful number, since it uses less digits than its factorization.

21577742 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10788873.

The product of its digits is 27440, while the sum is 35.

The square root of 21577742 is about 4645.1848187128. The cubic root of 21577742 is about 278.3996374324.

The spelling of 21577742 in words is "twenty-one million, five hundred seventy-seven thousand, seven hundred forty-two".