21488420 has 24 divisors (see below), whose sum is σ = 46683000. Its totient is φ = 8298752.

The previous prime is 21488399. The next prime is 21488429. The reversal of 21488420 is 2488412.

It can be written as a sum of positive squares in 4 ways, for example, as 401956 + 21086464 = 634^2 + 4592^2 .

It is a Harshad number since it is a multiple of its sum of digits (29).

It is not an unprimeable number, because it can be changed into a prime (21488429) 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, 17945 + ... + 19104.

It is an arithmetic number, because the mean of its divisors is an integer number (1945125).

Almost surely, 2^21488420 is an apocalyptic number.

21488420 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21488420 is an abundant number, since it is smaller than the sum of its proper divisors (25194580).

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

21488420 is a wasteful number, since it uses less digits than its factorization.

21488420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 37087 (or 37085 counting only the distinct ones).

The product of its (nonzero) digits is 4096, while the sum is 29.

The square root of 21488420 is about 4635.5603760495. The cubic root of 21488420 is about 278.0149570132.

The spelling of 21488420 in words is "twenty-one million, four hundred eighty-eight thousand, four hundred twenty".