21969946 has 4 divisors (see below), whose sum is σ = 32954922. Its totient is φ = 10984972.

The previous prime is 21969919. The next prime is 21969977. The reversal of 21969946 is 64996912.

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

It can be written as a sum of positive squares in only one way, i.e., 21724921 + 245025 = 4661^2 + 495^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21969896 and 21969905.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5492485 + ... + 5492488.

Almost surely, 2^21969946 is an apocalyptic number.

21969946 is a deficient number, since it is larger than the sum of its proper divisors (10984976).

21969946 is a wasteful number, since it uses less digits than its factorization.

21969946 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10984975.

The product of its digits is 209952, while the sum is 46.

The square root of 21969946 is about 4687.2108977515. The cubic root of 21969946 is about 280.0762802375.

It can be divided in two parts, 2196994 and 6, that added together give a cube (2197000 = 130³).

The spelling of 21969946 in words is "twenty-one million, nine hundred sixty-nine thousand, nine hundred forty-six".