21628726 has 32 divisors (see below), whose sum is σ = 41333760. Its totient is φ = 8263296.

The previous prime is 21628723. The next prime is 21628729. The reversal of 21628726 is 62782612.

It is an interprime number because it is at equal distance from previous prime (21628723) and next prime (21628729).

It is a Harshad number since it is a multiple of its sum of digits (34).

It is a junction number, because it is equal to n+sod(n) for n = 21628691 and 21628700.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21628723) 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 15 ways as a sum of consecutive naturals, for example, 2131 + ... + 6913.

It is an arithmetic number, because the mean of its divisors is an integer number (1291680).

Almost surely, 2^21628726 is an apocalyptic number.

21628726 is a deficient number, since it is larger than the sum of its proper divisors (19705034).

21628726 is a wasteful number, since it uses less digits than its factorization.

21628726 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4828.

The product of its digits is 16128, while the sum is 34.

The square root of 21628726 is about 4650.6694141811. The cubic root of 21628726 is about 278.6187329955.

The spelling of 21628726 in words is "twenty-one million, six hundred twenty-eight thousand, seven hundred twenty-six".