21994505 has 12 divisors (see below), whose sum is σ = 28580940. Its totient is φ = 16241472.

The previous prime is 21994487. The next prime is 21994513. The reversal of 21994505 is 50549912.

It can be written as a sum of positive squares in 6 ways, for example, as 10291264 + 11703241 = 3208^2 + 3421^2 .

It is not a de Polignac number, because 21994505 - 2¹⁰ = 21993481 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 12170 + ... + 13859.

It is an arithmetic number, because the mean of its divisors is an integer number (2381745).

Almost surely, 2^21994505 is an apocalyptic number.

It is an amenable number.

21994505 is a deficient number, since it is larger than the sum of its proper divisors (6586435).

21994505 is a wasteful number, since it uses less digits than its factorization.

21994505 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26060 (or 26047 counting only the distinct ones).

The product of its (nonzero) digits is 16200, while the sum is 35.

The square root of 21994505 is about 4689.8299542734. The cubic root of 21994505 is about 280.1806020228.

The spelling of 21994505 in words is "twenty-one million, nine hundred ninety-four thousand, five hundred five".