21945370 has 8 divisors (see below), whose sum is σ = 39501684. Its totient is φ = 8778144.

The previous prime is 21945367. The next prime is 21945383. The reversal of 21945370 is 7354912.

It can be written as a sum of positive squares in 2 ways, for example, as 17614809 + 4330561 = 4197^2 + 2081^2 .

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

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 3 ways as a sum of consecutive naturals, for example, 1097259 + ... + 1097278.

Almost surely, 2^21945370 is an apocalyptic number.

21945370 is a deficient number, since it is larger than the sum of its proper divisors (17556314).

21945370 is a wasteful number, since it uses less digits than its factorization.

21945370 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2194544.

The product of its (nonzero) digits is 7560, while the sum is 31.

The square root of 21945370 is about 4684.5885625101. The cubic root of 21945370 is about 279.9718083861.

The spelling of 21945370 in words is "twenty-one million, nine hundred forty-five thousand, three hundred seventy".