21877744 has 40 divisors (see below), whose sum is σ = 48712160. Its totient is φ = 9324288.

The previous prime is 21877733. The next prime is 21877771. The reversal of 21877744 is 44777812.

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

It is a junction number, because it is equal to n+sod(n) for n = 21877697 and 21877706.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 25222 + ... + 26074.

It is an arithmetic number, because the mean of its divisors is an integer number (1217804).

Almost surely, 2^21877744 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 21877744, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24356080).

21877744 is an abundant number, since it is smaller than the sum of its proper divisors (26834416).

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

21877744 is a wasteful number, since it uses less digits than its factorization.

21877744 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1097 (or 1091 counting only the distinct ones).

The product of its digits is 87808, while the sum is 40.

The square root of 21877744 is about 4677.3650702078. The cubic root of 21877744 is about 279.6839290598.

The spelling of 21877744 in words is "twenty-one million, eight hundred seventy-seven thousand, seven hundred forty-four".