21728862 has 12 divisors (see below), whose sum is σ = 47079240. Its totient is φ = 7242948.

The previous prime is 21728857. The next prime is 21728867. The reversal of 21728862 is 26882712.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21728857) and next prime (21728867).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21728867) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 603562 + ... + 603597.

It is an arithmetic number, because the mean of its divisors is an integer number (3923270).

Almost surely, 2^21728862 is an apocalyptic number.

21728862 is an abundant number, since it is smaller than the sum of its proper divisors (25350378).

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

21728862 is a wasteful number, since it uses less digits than its factorization.

21728862 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1207167 (or 1207164 counting only the distinct ones).

The product of its digits is 21504, while the sum is 36.

The square root of 21728862 is about 4661.4227441844. The cubic root of 21728862 is about 279.0480512297.

The spelling of 21728862 in words is "twenty-one million, seven hundred twenty-eight thousand, eight hundred sixty-two".