21626740 has 12 divisors (see below), whose sum is σ = 45416196. Its totient is φ = 8650688.

The previous prime is 21626719. The next prime is 21626743. The reversal of 21626740 is 4762612.

It can be written as a sum of positive squares in 2 ways, for example, as 13942756 + 7683984 = 3734^2 + 2772^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21626699 and 21626708.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21626743) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 540649 + ... + 540688.

It is an arithmetic number, because the mean of its divisors is an integer number (3784683).

Almost surely, 2^21626740 is an apocalyptic number.

21626740 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21626740 is an abundant number, since it is smaller than the sum of its proper divisors (23789456).

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

21626740 is a wasteful number, since it uses less digits than its factorization.

21626740 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1081346 (or 1081344 counting only the distinct ones).

The product of its (nonzero) digits is 4032, while the sum is 28.

The square root of 21626740 is about 4650.4558916304. The cubic root of 21626740 is about 278.6102049275.

It can be divided in two parts, 21626 and 740, that added together give a triangular number (22366 = T₂₁₁).

The spelling of 21626740 in words is "twenty-one million, six hundred twenty-six thousand, seven hundred forty".