21942811 has 16 divisors (see below), whose sum is σ = 24530688. Its totient is φ = 19461600.

The previous prime is 21942799. The next prime is 21942827. The reversal of 21942811 is 11824912.

It is a cyclic number.

It is not a de Polignac number, because 21942811 - 2¹⁵ = 21910043 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 21942811.

It is not an unprimeable number, because it can be changed into a prime (21942871) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 121141 + ... + 121321.

It is an arithmetic number, because the mean of its divisors is an integer number (1533168).

Almost surely, 2^21942811 is an apocalyptic number.

21942811 is a deficient number, since it is larger than the sum of its proper divisors (2587877).

21942811 is a wasteful number, since it uses less digits than its factorization.

21942811 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 402.

The product of its digits is 1152, while the sum is 28.

The square root of 21942811 is about 4684.3154249047. The cubic root of 21942811 is about 279.9609256698.

It can be divided in two parts, 2194 and 2811, that added together give a palindrome (5005).

The spelling of 21942811 in words is "twenty-one million, nine hundred forty-two thousand, eight hundred eleven".