21742072 has 16 divisors (see below), whose sum is σ = 44472600. Its totient is φ = 9882720.

The previous prime is 21742043. The next prime is 21742087. The reversal of 21742072 is 27024712.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 123447 + ... + 123622.

Almost surely, 2^21742072 is an apocalyptic number.

21742072 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is an amenable number.

21742072 is an abundant number, since it is smaller than the sum of its proper divisors (22730528).

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

21742072 is a wasteful number, since it uses less digits than its factorization.

21742072 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 247086 (or 247082 counting only the distinct ones).

The product of its (nonzero) digits is 1568, while the sum is 25.

The square root of 21742072 is about 4662.8394782579. The cubic root of 21742072 is about 279.1045885977.

Adding to 21742072 its reverse (27024712), we get a palindrome (48766784).

The spelling of 21742072 in words is "twenty-one million, seven hundred forty-two thousand, seventy-two".