21249396 has 144 divisors (see below), whose sum is σ = 65729664. Its totient is φ = 5660928.

The previous prime is 21249331. The next prime is 21249443. The reversal of 21249396 is 69394212.

21249396 is a `hidden beast` number, since 21 + 249 + 396 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

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

It is a self number, because there is not a number n which added to its sum of digits gives 21249396.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 400906 + ... + 400958.

It is an arithmetic number, because the mean of its divisors is an integer number (456456).

Almost surely, 2^21249396 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21249396, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32864832).

21249396 is an abundant number, since it is smaller than the sum of its proper divisors (44480268).

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

21249396 is a wasteful number, since it uses less digits than its factorization.

21249396 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 150 (or 145 counting only the distinct ones).

The product of its digits is 23328, while the sum is 36.

The square root of 21249396 is about 4609.7067151826. The cubic root of 21249396 is about 276.9802885355.

The spelling of 21249396 in words is "twenty-one million, two hundred forty-nine thousand, three hundred ninety-six".