21175020 has 72 divisors (see below), whose sum is σ = 66625104. Its totient is φ = 5645376.

The previous prime is 21174977. The next prime is 21175031. The reversal of 21175020 is 2057112.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 21174984 and 21175002.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2682 + ... + 7038.

Almost surely, 2^21175020 is an apocalyptic number.

21175020 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 21175020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33312552).

21175020 is an abundant number, since it is smaller than the sum of its proper divisors (45450084).

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

21175020 is a wasteful number, since it uses less digits than its factorization.

21175020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4381 (or 4367 counting only the distinct ones).

The product of its (nonzero) digits is 140, while the sum is 18.

The square root of 21175020 is about 4601.6323190798. The cubic root of 21175020 is about 276.6567535681.

The spelling of 21175020 in words is "twenty-one million, one hundred seventy-five thousand, twenty".