21706426 has 16 divisors (see below), whose sum is σ = 37574784. Its totient is φ = 9211824.

The previous prime is 21706387. The next prime is 21706427. The reversal of 21706426 is 62460712.

It is a junction number, because it is equal to n+sod(n) for n = 21706394 and 21706403.

It is not an unprimeable number, because it can be changed into a prime (21706427) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6085 + ... + 8968.

It is an arithmetic number, because the mean of its divisors is an integer number (2348424).

Almost surely, 2^21706426 is an apocalyptic number.

21706426 is a deficient number, since it is larger than the sum of its proper divisors (15868358).

21706426 is a wasteful number, since it uses less digits than its factorization.

21706426 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15165.

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

The square root of 21706426 is about 4659.0155612533. The cubic root of 21706426 is about 278.9519750502.

The spelling of 21706426 in words is "twenty-one million, seven hundred six thousand, four hundred twenty-six".