21291103 has 4 divisors (see below), whose sum is σ = 21502008. Its totient is φ = 21080200.

The previous prime is 21291097. The next prime is 21291113. The reversal of 21291103 is 30119212.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21291103 is a prime.

It is a super-2 number, since 2×21291103² = 906622133913218, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21291113) 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, 105301 + ... + 105502.

It is an arithmetic number, because the mean of its divisors is an integer number (5375502).

Almost surely, 2^21291103 is an apocalyptic number.

21291103 is a deficient number, since it is larger than the sum of its proper divisors (210905).

21291103 is a wasteful number, since it uses less digits than its factorization.

21291103 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 210904.

The product of its (nonzero) digits is 108, while the sum is 19.

The square root of 21291103 is about 4614.2283211822. The cubic root of 21291103 is about 277.1613833654.

The spelling of 21291103 in words is "twenty-one million, two hundred ninety-one thousand, one hundred three".