21020130 has 24 divisors (see below), whose sum is σ = 54652572. Its totient is φ = 5605344.

The previous prime is 21020119. The next prime is 21020159. The reversal of 21020130 is 3102012.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 17413929 + 3606201 = 4173^2 + 1899^2 .

It is a Harshad number since it is a multiple of its sum of digits (9).

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 116689 + ... + 116868.

Almost surely, 2^21020130 is an apocalyptic number.

21020130 is an abundant number, since it is smaller than the sum of its proper divisors (33632442).

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

21020130 is a wasteful number, since it uses less digits than its factorization.

21020130 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 233570 (or 233567 counting only the distinct ones).

The product of its (nonzero) digits is 12, while the sum is 9.

The square root of 21020130 is about 4584.7715319305. The cubic root of 21020130 is about 275.9805436820.

Adding to 21020130 its reverse (3102012), we get a palindrome (24122142).

The spelling of 21020130 in words is "twenty-one million, twenty thousand, one hundred thirty".