21477420 has 96 divisors (see below), whose sum is σ = 69027840. Its totient is φ = 5538240.

The previous prime is 21477419. The next prime is 21477439. The reversal of 21477420 is 2477412.

It is a happy number.

It is a super-2 number, since 2×21477420² = 922559139712800, which contains 22 as substring.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 16099 + ... + 17381.

It is an arithmetic number, because the mean of its divisors is an integer number (719040).

Almost surely, 2^21477420 is an apocalyptic number.

21477420 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 21477420, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34513920).

21477420 is an abundant number, since it is smaller than the sum of its proper divisors (47550420).

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

21477420 is a wasteful number, since it uses less digits than its factorization.

21477420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1332 (or 1324 counting only the distinct ones).

The product of its (nonzero) digits is 3136, while the sum is 27.

The square root of 21477420 is about 4634.3737440996. The cubic root of 21477420 is about 277.9675099618.

The spelling of 21477420 in words is "twenty-one million, four hundred seventy-seven thousand, four hundred twenty".