21103693 has 4 divisors (see below), whose sum is σ = 22727068. Its totient is φ = 19480320.

The previous prime is 21103679. The next prime is 21103697. The reversal of 21103693 is 39630112.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 5207524 + 15896169 = 2282^2 + 3987^2 .

It is a cyclic number.

It is not a de Polignac number, because 21103693 - 2¹⁷ = 20972621 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21103697) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 811668 + ... + 811693.

It is an arithmetic number, because the mean of its divisors is an integer number (5681767).

Almost surely, 2^21103693 is an apocalyptic number.

It is an amenable number.

21103693 is a deficient number, since it is larger than the sum of its proper divisors (1623375).

21103693 is a wasteful number, since it uses less digits than its factorization.

21103693 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1623374.

The product of its (nonzero) digits is 972, while the sum is 25.

The square root of 21103693 is about 4593.8755969225. The cubic root of 21103693 is about 276.3457692972.

The spelling of 21103693 in words is "twenty-one million, one hundred three thousand, six hundred ninety-three".