21142772 has 24 divisors (see below), whose sum is σ = 42686784. Its totient is φ = 8975232.

The previous prime is 21142753. The next prime is 21142777. The reversal of 21142772 is 27724112.

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21142777) 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, 533 + ... + 6524.

It is an arithmetic number, because the mean of its divisors is an integer number (1778616).

Almost surely, 2^21142772 is an apocalyptic number.

It is an amenable number.

21142772 is an abundant number, since it is smaller than the sum of its proper divisors (21544012).

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

21142772 is a wasteful number, since it uses less digits than its factorization.

21142772 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7175 (or 7173 counting only the distinct ones).

The product of its digits is 1568, while the sum is 26.

The square root of 21142772 is about 4598.1270099900. The cubic root of 21142772 is about 276.5162395754.

Adding to 21142772 its reverse (27724112), we get a palindrome (48866884).

The spelling of 21142772 in words is "twenty-one million, one hundred forty-two thousand, seven hundred seventy-two".