21773772 has 96 divisors (see below), whose sum is σ = 60614400. Its totient is φ = 6823440.

The previous prime is 21773771. The next prime is 21773777. The reversal of 21773772 is 27737712.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is not an unprimeable number, because it can be changed into a prime (21773771) by changing a digit.

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 31 ways as a sum of consecutive naturals, for example, 166147 + ... + 166277.

It is an arithmetic number, because the mean of its divisors is an integer number (631400).

Almost surely, 2^21773772 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21773772, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30307200).

21773772 is an abundant number, since it is smaller than the sum of its proper divisors (38840628).

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

21773772 is a wasteful number, since it uses less digits than its factorization.

21773772 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 175 (or 155 counting only the distinct ones).

The product of its digits is 28812, while the sum is 36.

The square root of 21773772 is about 4666.2374564525. The cubic root of 21773772 is about 279.2401678100.

The spelling of 21773772 in words is "twenty-one million, seven hundred seventy-three thousand, seven hundred seventy-two".