21235742 has 12 divisors (see below), whose sum is σ = 35013048. Its totient is φ = 9652500.

The previous prime is 21235741. The next prime is 21235759. The reversal of 21235742 is 24753212.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21235741) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 43634 + ... + 44117.

It is an arithmetic number, because the mean of its divisors is an integer number (2917754).

Almost surely, 2^21235742 is an apocalyptic number.

21235742 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

21235742 is a deficient number, since it is larger than the sum of its proper divisors (13777306).

21235742 is a wasteful number, since it uses less digits than its factorization.

21235742 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 87775 (or 87764 counting only the distinct ones).

The product of its digits is 3360, while the sum is 26.

The square root of 21235742 is about 4608.2254719143. The cubic root of 21235742 is about 276.9209503912.

Adding to 21235742 its reverse (24753212), we get a palindrome (45988954).

The spelling of 21235742 in words is "twenty-one million, two hundred thirty-five thousand, seven hundred forty-two".