21478392 has 64 divisors (see below), whose sum is σ = 64260000. Its totient is φ = 6607872.

The previous prime is 21478363. The next prime is 21478393. The reversal of 21478392 is 29387412.

It is a super-2 number, since 2×21478392² = 922642645811328, which contains 22 as substring.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21478393) 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, 1017 + ... + 6632.

Almost surely, 2^21478392 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 21478392, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32130000).

21478392 is an abundant number, since it is smaller than the sum of its proper divisors (42781608).

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

21478392 is a wasteful number, since it uses less digits than its factorization.

21478392 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7677 (or 7667 counting only the distinct ones).

The product of its digits is 24192, while the sum is 36.

The square root of 21478392 is about 4634.4786114513. The cubic root of 21478392 is about 277.9717032082.

It can be divided in two parts, 214 and 78392, that added together give a triangular number (78606 = T₃₉₆).

The spelling of 21478392 in words is "twenty-one million, four hundred seventy-eight thousand, three hundred ninety-two".