21742158 has 16 divisors (see below), whose sum is σ = 43540560. Its totient is φ = 7238016.

The previous prime is 21742157. The next prime is 21742159. The reversal of 21742158 is 85124712.

It is an interprime number because it is at equal distance from previous prime (21742157) and next prime (21742159).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21742151) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4008 + ... + 7716.

It is an arithmetic number, because the mean of its divisors is an integer number (2721285).

Almost surely, 2^21742158 is an apocalyptic number.

21742158 is an abundant number, since it is smaller than the sum of its proper divisors (21798402).

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

21742158 is a wasteful number, since it uses less digits than its factorization.

21742158 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4691.

The product of its digits is 4480, while the sum is 30.

The square root of 21742158 is about 4662.8487000974. The cubic root of 21742158 is about 279.1049565933.

The spelling of 21742158 in words is "twenty-one million, seven hundred forty-two thousand, one hundred fifty-eight".