21948420 has 96 divisors (see below), whose sum is σ = 69713280. Its totient is φ = 5114880.

The previous prime is 21948397. The next prime is 21948427. The reversal of 21948420 is 2484912.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is not an unprimeable number, because it can be changed into a prime (21948427) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 14080 + ... + 15560.

It is an arithmetic number, because the mean of its divisors is an integer number (726180).

Almost surely, 2^21948420 is an apocalyptic number.

21948420 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21948420, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34856640).

21948420 is an abundant number, since it is smaller than the sum of its proper divisors (47764860).

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

21948420 is a wasteful number, since it uses less digits than its factorization.

21948420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1525 (or 1523 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 30.

The square root of 21948420 is about 4684.9140867256. The cubic root of 21948420 is about 279.9847780841.

The spelling of 21948420 in words is "twenty-one million, nine hundred forty-eight thousand, four hundred twenty".