21351011 has 16 divisors (see below), whose sum is σ = 23885280. Its totient is φ = 18923520.

The previous prime is 21351007. The next prime is 21351013. The reversal of 21351011 is 11015312.

It is not a de Polignac number, because 21351011 - 2² = 21351007 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21351013) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 110531 + ... + 110723.

It is an arithmetic number, because the mean of its divisors is an integer number (1492830).

Almost surely, 2^21351011 is an apocalyptic number.

21351011 is a deficient number, since it is larger than the sum of its proper divisors (2534269).

21351011 is a wasteful number, since it uses less digits than its factorization.

21351011 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 406.

The product of its (nonzero) digits is 30, while the sum is 14.

The square root of 21351011 is about 4620.7154207980. The cubic root of 21351011 is about 277.4210948996.

Adding to 21351011 its reverse (11015312), we get a palindrome (32366323).

The spelling of 21351011 in words is "twenty-one million, three hundred fifty-one thousand, eleven".