21772740 has 72 divisors (see below), whose sum is σ = 67032000. Its totient is φ = 5276480.

The previous prime is 21772691. The next prime is 21772741. The reversal of 21772740 is 4727712.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 21772698 and 21772707.

It is not an unprimeable number, because it can be changed into a prime (21772741) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 5761 + ... + 8759.

It is an arithmetic number, because the mean of its divisors is an integer number (931000).

Almost surely, 2^21772740 is an apocalyptic number.

21772740 is a gapful number since it is divisible by the number (20) 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 21772740, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33516000).

21772740 is an abundant number, since it is smaller than the sum of its proper divisors (45259260).

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

21772740 is a wasteful number, since it uses less digits than its factorization.

21772740 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3033 (or 3020 counting only the distinct ones).

The product of its (nonzero) digits is 5488, while the sum is 30.

The square root of 21772740 is about 4666.1268735430. The cubic root of 21772740 is about 279.2357560740.

The spelling of 21772740 in words is "twenty-one million, seven hundred seventy-two thousand, seven hundred forty".