21047826 has 8 divisors (see below), whose sum is σ = 42095664. Its totient is φ = 7015940.

The previous prime is 21047813. The next prime is 21047827. The reversal of 21047826 is 62874012.

It is a sphenic number, since it is the product of 3 distinct primes.

21047826 is an admirable number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21047793 and 21047802.

It is not an unprimeable number, because it can be changed into a prime (21047827) 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, 1753980 + ... + 1753991.

It is an arithmetic number, because the mean of its divisors is an integer number (5261958).

Almost surely, 2^21047826 is an apocalyptic number.

21047826 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

21047826 is a wasteful number, since it uses less digits than its factorization.

21047826 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3507976.

The product of its (nonzero) digits is 5376, while the sum is 30.

The square root of 21047826 is about 4587.7909716987. The cubic root of 21047826 is about 276.1017006010.

The spelling of 21047826 in words is "twenty-one million, forty-seven thousand, eight hundred twenty-six".