21356011 has 4 divisors (see below), whose sum is σ = 21407400. Its totient is φ = 21304624.

The previous prime is 21356003. The next prime is 21356047. The reversal of 21356011 is 11065312.

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

It is a cyclic number.

It is not a de Polignac number, because 21356011 - 2³ = 21356003 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21356011.

It is not an unprimeable number, because it can be changed into a prime (21356051) 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, 25066 + ... + 25903.

It is an arithmetic number, because the mean of its divisors is an integer number (5351850).

Almost surely, 2^21356011 is an apocalyptic number.

21356011 is a deficient number, since it is larger than the sum of its proper divisors (51389).

21356011 is an equidigital number, since it uses as much as digits as its factorization.

21356011 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 51388.

The product of its (nonzero) digits is 180, while the sum is 19.

The square root of 21356011 is about 4621.2564308854. The cubic root of 21356011 is about 277.4427487877.

The spelling of 21356011 in words is "twenty-one million, three hundred fifty-six thousand, eleven".