21790726 has 4 divisors (see below), whose sum is σ = 32686092. Its totient is φ = 10895362.

The previous prime is 21790711. The next prime is 21790801. The reversal of 21790726 is 62709712.

It is a semiprime because it is the product of two primes.

It is a junction number, because it is equal to n+sod(n) for n = 21790691 and 21790700.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5447680 + ... + 5447683.

It is an arithmetic number, because the mean of its divisors is an integer number (8171523).

Almost surely, 2^21790726 is an apocalyptic number.

21790726 is a deficient number, since it is larger than the sum of its proper divisors (10895366).

21790726 is a wasteful number, since it uses less digits than its factorization.

21790726 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10895365.

The product of its (nonzero) digits is 10584, while the sum is 34.

The square root of 21790726 is about 4668.0537700416. The cubic root of 21790726 is about 279.3126251619.

The spelling of 21790726 in words is "twenty-one million, seven hundred ninety thousand, seven hundred twenty-six".