21994370 has 16 divisors (see below), whose sum is σ = 39667320. Its totient is φ = 8780544.

The previous prime is 21994369. The next prime is 21994393. The reversal of 21994370 is 7349912.

It can be written as a sum of positive squares in 4 ways, for example, as 16410601 + 5583769 = 4051^2 + 2363^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 21994370.

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 in 7 ways as a sum of consecutive naturals, for example, 4076 + ... + 7784.

Almost surely, 2^21994370 is an apocalyptic number.

21994370 is a deficient number, since it is larger than the sum of its proper divisors (17672950).

21994370 is a wasteful number, since it uses less digits than its factorization.

21994370 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4309.

The product of its (nonzero) digits is 13608, while the sum is 35.

The square root of 21994370 is about 4689.8155614054. The cubic root of 21994370 is about 280.1800287817.

The spelling of 21994370 in words is "twenty-one million, nine hundred ninety-four thousand, three hundred seventy".