21880646 has 4 divisors (see below), whose sum is σ = 32820972. Its totient is φ = 10940322.

The previous prime is 21880643. The next prime is 21880657. The reversal of 21880646 is 64608812.

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

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21880643) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5470160 + ... + 5470163.

It is an arithmetic number, because the mean of its divisors is an integer number (8205243).

Almost surely, 2^21880646 is an apocalyptic number.

21880646 is a deficient number, since it is larger than the sum of its proper divisors (10940326).

21880646 is a wasteful number, since it uses less digits than its factorization.

21880646 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10940325.

The product of its (nonzero) digits is 18432, while the sum is 35.

The square root of 21880646 is about 4677.6752773146. The cubic root of 21880646 is about 279.6962948516.

The spelling of 21880646 in words is "twenty-one million, eight hundred eighty thousand, six hundred forty-six".