21760129 has 4 divisors (see below), whose sum is σ = 21774676. Its totient is φ = 21745584.

The previous prime is 21760127. The next prime is 21760133. The reversal of 21760129 is 92106712.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 6760000 + 15000129 = 2600^2 + 3873^2 .

It is a cyclic number.

It is not a de Polignac number, because 21760129 - 2¹ = 21760127 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21760097 and 21760106.

It is not an unprimeable number, because it can be changed into a prime (21760127) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4734 + ... + 8119.

It is an arithmetic number, because the mean of its divisors is an integer number (5443669).

Almost surely, 2^21760129 is an apocalyptic number.

It is an amenable number.

21760129 is a deficient number, since it is larger than the sum of its proper divisors (14547).

21760129 is a wasteful number, since it uses less digits than its factorization.

21760129 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14546.

The product of its (nonzero) digits is 1512, while the sum is 28.

The square root of 21760129 is about 4664.7753429292. The cubic root of 21760129 is about 279.1818335662.

The spelling of 21760129 in words is "twenty-one million, seven hundred sixty thousand, one hundred twenty-nine".