21276020 has 24 divisors (see below), whose sum is σ = 44767464. Its totient is φ = 8493696.

The previous prime is 21275983. The next prime is 21276023. The reversal of 21276020 is 2067212.

It can be written as a sum of positive squares in 4 ways, for example, as 1008016 + 20268004 = 1004^2 + 4502^2 .

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a junction number, because it is equal to n+sod(n) for n = 21275983 and 21276001.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21276023) 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 7 ways as a sum of consecutive naturals, for example, 16934 + ... + 18146.

It is an arithmetic number, because the mean of its divisors is an integer number (1865311).

Almost surely, 2^21276020 is an apocalyptic number.

21276020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21276020 is an abundant number, since it is smaller than the sum of its proper divisors (23491444).

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

21276020 is a wasteful number, since it uses less digits than its factorization.

With its successor (21276021) it forms an eRAP, since the sums of their prime factors are consecutive (2099 and 2100).

21276020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2099 (or 2097 counting only the distinct ones).

The product of its (nonzero) digits is 336, while the sum is 20.

The square root of 21276020 is about 4612.5936304860. The cubic root of 21276020 is about 277.0959192027.

The spelling of 21276020 in words is "twenty-one million, two hundred seventy-six thousand, twenty".