21711937 has 6 divisors (see below), whose sum is σ = 23510742. Its totient is φ = 20041632.

The previous prime is 21711917. The next prime is 21711959. The reversal of 21711937 is 73911712.

It can be written as a sum of positive squares in 3 ways, for example, as 1962801 + 19749136 = 1401^2 + 4444^2 .

It is not a de Polignac number, because 21711937 - 2¹⁵ = 21679169 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21711899 and 21711908.

It is not an unprimeable number, because it can be changed into a prime (21711917) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 64068 + ... + 64405.

It is an arithmetic number, because the mean of its divisors is an integer number (3918457).

Almost surely, 2^21711937 is an apocalyptic number.

It is an amenable number.

21711937 is a deficient number, since it is larger than the sum of its proper divisors (1798805).

21711937 is a wasteful number, since it uses less digits than its factorization.

21711937 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 128499 (or 128486 counting only the distinct ones).

The product of its digits is 2646, while the sum is 31.

The square root of 21711937 is about 4659.6069576736. The cubic root of 21711937 is about 278.9755805677.

It can be divided in two parts, 217119 and 37, that added together give a square (217156 = 466²).

The spelling of 21711937 in words is "twenty-one million, seven hundred eleven thousand, nine hundred thirty-seven".