21613378 has 8 divisors (see below), whose sum is σ = 32471100. Its totient is φ = 10789680.

The previous prime is 21613367. The next prime is 21613379. The reversal of 21613378 is 87331612.

It can be written as a sum of positive squares in 2 ways, for example, as 21594609 + 18769 = 4647^2 + 137^2 .

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 (21613379) 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, 6853 + ... + 9496.

Almost surely, 2^21613378 is an apocalyptic number.

21613378 is a deficient number, since it is larger than the sum of its proper divisors (10857722).

21613378 is a wasteful number, since it uses less digits than its factorization.

21613378 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17012.

The product of its digits is 6048, while the sum is 31.

The square root of 21613378 is about 4649.0190363129. The cubic root of 21613378 is about 278.5528136837.

The spelling of 21613378 in words is "twenty-one million, six hundred thirteen thousand, three hundred seventy-eight".