21761204 has 6 divisors (see below), whose sum is σ = 38082114. Its totient is φ = 10880600.

The previous prime is 21761191. The next prime is 21761219. The reversal of 21761204 is 40216712.

It can be written as a sum of positive squares in only one way, i.e., 18905104 + 2856100 = 4348^2 + 1690^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 21761204.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2720147 + ... + 2720154.

It is an arithmetic number, because the mean of its divisors is an integer number (6347019).

Almost surely, 2^21761204 is an apocalyptic number.

It is an amenable number.

21761204 is a deficient number, since it is larger than the sum of its proper divisors (16320910).

21761204 is a wasteful number, since it uses less digits than its factorization.

21761204 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5440305 (or 5440303 counting only the distinct ones).

The product of its (nonzero) digits is 672, while the sum is 23.

The square root of 21761204 is about 4664.8905667765. The cubic root of 21761204 is about 279.1864308969.

Adding to 21761204 its reverse (40216712), we get a palindrome (61977916).

The spelling of 21761204 in words is "twenty-one million, seven hundred sixty-one thousand, two hundred four".