21966123 has 8 divisors (see below), whose sum is σ = 30079888. Its totient is φ = 14248224.

The previous prime is 21966107. The next prime is 21966143. The reversal of 21966123 is 32166912.

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

It is not a de Polignac number, because 21966123 - 2⁴ = 21966107 is a prime.

It is a super-2 number, since 2×21966123² = 965021119302258, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21966103) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 98836 + ... + 99057.

It is an arithmetic number, because the mean of its divisors is an integer number (3759986).

Almost surely, 2^21966123 is an apocalyptic number.

21966123 is a deficient number, since it is larger than the sum of its proper divisors (8113765).

21966123 is a wasteful number, since it uses less digits than its factorization.

21966123 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 197933.

The product of its digits is 3888, while the sum is 30.

The square root of 21966123 is about 4686.8030681905. The cubic root of 21966123 is about 280.0600338961.

The spelling of 21966123 in words is "twenty-one million, nine hundred sixty-six thousand, one hundred twenty-three".