21019726 has 32 divisors (see below), whose sum is σ = 39614400. Its totient is φ = 8311968.

The previous prime is 21019699. The next prime is 21019727. The reversal of 21019726 is 62791012.

It is a happy number.

It is a super-2 number, since 2×21019726² = 883657762230152, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21019694 and 21019703.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21019727) 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, 7740 + ... + 10096.

It is an arithmetic number, because the mean of its divisors is an integer number (1237950).

Almost surely, 2^21019726 is an apocalyptic number.

21019726 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

21019726 is a deficient number, since it is larger than the sum of its proper divisors (18594674).

21019726 is a wasteful number, since it uses less digits than its factorization.

21019726 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2393 (or 2379 counting only the distinct ones).

The product of its (nonzero) digits is 1512, while the sum is 28.

The square root of 21019726 is about 4584.7274728167. The cubic root of 21019726 is about 275.9787755856.

The spelling of 21019726 in words is "twenty-one million, nineteen thousand, seven hundred twenty-six".