21277872 has 240 divisors, whose sum is σ = 78923520. Its totient is φ = 5184000.

The previous prime is 21277871. The next prime is 21277901. The reversal of 21277872 is 27877212.

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

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

It is not an unprimeable number, because it can be changed into a prime (21277871) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 210622 + ... + 210722.

It is an arithmetic number, because the mean of its divisors is an integer number (328848).

Almost surely, 2^21277872 is an apocalyptic number.

21277872 is a gapful number since it is divisible by the number (22) 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 21277872, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39461760).

21277872 is an abundant number, since it is smaller than the sum of its proper divisors (57645648).

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

21277872 is a wasteful number, since it uses less digits than its factorization.

21277872 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 152 (or 143 counting only the distinct ones).

The product of its digits is 21952, while the sum is 36.

The square root of 21277872 is about 4612.7943808499. The cubic root of 21277872 is about 277.1039590327.

It can be divided in two parts, 2127 and 7872, that added together give a palindrome (9999).

The spelling of 21277872 in words is "twenty-one million, two hundred seventy-seven thousand, eight hundred seventy-two".