21406011 has 16 divisors (see below), whose sum is σ = 31726080. Its totient is φ = 12727520.

The previous prime is 21406001. The next prime is 21406037. The reversal of 21406011 is 11060412.

It is a cyclic number.

It is not a de Polignac number, because 21406011 - 2¹⁵ = 21373243 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21406001) 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, 4371 + ... + 7868.

It is an arithmetic number, because the mean of its divisors is an integer number (1982880).

Almost surely, 2^21406011 is an apocalyptic number.

21406011 is a deficient number, since it is larger than the sum of its proper divisors (10320069).

21406011 is a wasteful number, since it uses less digits than its factorization.

21406011 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12306.

The product of its (nonzero) digits is 48, while the sum is 15.

The square root of 21406011 is about 4626.6630523521. The cubic root of 21406011 is about 277.6591020102.

Adding to 21406011 its reverse (11060412), we get a palindrome (32466423).

The spelling of 21406011 in words is "twenty-one million, four hundred six thousand, eleven".