21123396 has 48 divisors (see below), whose sum is σ = 62590080. Its totient is φ = 6035040.

The previous prime is 21123391. The next prime is 21123457. The reversal of 21123396 is 69332112.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a nude number because it is divisible by every one of its digits.

It is not an unprimeable number, because it can be changed into a prime (21123391) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 13215 + ... + 14726.

It is an arithmetic number, because the mean of its divisors is an integer number (1303960).

Almost surely, 2^21123396 is an apocalyptic number.

It is an amenable number.

21123396 is an abundant number, since it is smaller than the sum of its proper divisors (41466684).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21123396 is a wasteful number, since it uses less digits than its factorization.

21123396 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27961 (or 27953 counting only the distinct ones).

The product of its digits is 1944, while the sum is 27.

The square root of 21123396 is about 4596.0195822037. The cubic root of 21123396 is about 276.4317439350.

The spelling of 21123396 in words is "twenty-one million, one hundred twenty-three thousand, three hundred ninety-six".