21742344 has 160 divisors (see below), whose sum is σ = 68607000. Its totient is φ = 6386688.

The previous prime is 21742333. The next prime is 21742363. The reversal of 21742344 is 44324712.

It can be written as a sum of positive squares in 4 ways, for example, as 11819844 + 9922500 = 3438^2 + 3150^2 .

It is a super-2 number, since 2×21742344² = 945459045228672, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 244252 + ... + 244340.

Almost surely, 2^21742344 is an apocalyptic number.

21742344 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21742344, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34303500).

21742344 is an abundant number, since it is smaller than the sum of its proper divisors (46864656).

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

21742344 is a wasteful number, since it uses less digits than its factorization.

21742344 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 149 (or 136 counting only the distinct ones).

The product of its digits is 5376, while the sum is 27.

The square root of 21742344 is about 4662.8686449438. The cubic root of 21742344 is about 279.1057524876.

The spelling of 21742344 in words is "twenty-one million, seven hundred forty-two thousand, three hundred forty-four".