21955742 has 4 divisors (see below), whose sum is σ = 32933616. Its totient is φ = 10977870.

The previous prime is 21955733. The next prime is 21955753. The reversal of 21955742 is 24755912.

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, 5488934 + ... + 5488937.

It is an arithmetic number, because the mean of its divisors is an integer number (8233404).

Almost surely, 2^21955742 is an apocalyptic number.

21955742 is a deficient number, since it is larger than the sum of its proper divisors (10977874).

21955742 is a wasteful number, since it uses less digits than its factorization.

21955742 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10977873.

The product of its digits is 25200, while the sum is 35.

The square root of 21955742 is about 4685.6954659901. The cubic root of 21955742 is about 280.0159089600.

The spelling of 21955742 in words is "twenty-one million, nine hundred fifty-five thousand, seven hundred forty-two".