21994945 has 8 divisors (see below), whose sum is σ = 30164544. Its totient is φ = 15082224.

The previous prime is 21994897. The next prime is 21994981. The reversal of 21994945 is 54949912.

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

It is a cyclic number.

It is not a de Polignac number, because 21994945 - 2¹¹ = 21992897 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 314179 + ... + 314248.

It is an arithmetic number, because the mean of its divisors is an integer number (3770568).

Almost surely, 2^21994945 is an apocalyptic number.

It is an amenable number.

21994945 is a deficient number, since it is larger than the sum of its proper divisors (8169599).

21994945 is an equidigital number, since it uses as much as digits as its factorization.

21994945 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 628439.

The product of its digits is 116640, while the sum is 43.

The square root of 21994945 is about 4689.8768640552. The cubic root of 21994945 is about 280.1824703476.

The spelling of 21994945 in words is "twenty-one million, nine hundred ninety-four thousand, nine hundred forty-five".