21988546 has 8 divisors (see below), whose sum is σ = 33787404. Its totient is φ = 10726080.

The previous prime is 21988541. The next prime is 21988559. The reversal of 21988546 is 64588912.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 19900521 + 2088025 = 4461^2 + 1445^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not an unprimeable number, because it can be changed into a prime (21988541) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 133995 + ... + 134158.

Almost surely, 2^21988546 is an apocalyptic number.

21988546 is a deficient number, since it is larger than the sum of its proper divisors (11798858).

21988546 is a wasteful number, since it uses less digits than its factorization.

21988546 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 268196.

The product of its digits is 138240, while the sum is 43.

The square root of 21988546 is about 4689.1946003552. The cubic root of 21988546 is about 280.1552965050.

The spelling of 21988546 in words is "twenty-one million, nine hundred eighty-eight thousand, five hundred forty-six".