21012130 has 8 divisors (see below), whose sum is σ = 37821852. Its totient is φ = 8404848.

The previous prime is 21012127. The next prime is 21012137. The reversal of 21012130 is 3121012.

It can be written as a sum of positive squares in 2 ways, for example, as 20985561 + 26569 = 4581^2 + 163^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a Harshad number since it is a multiple of its sum of digits (10), and also a Moran number because the ratio is a prime number: 2101213 = 21012130 / (2 + 1 + 0 + 1 + 2 + 1 + 3 + 0).

It is not an unprimeable number, because it can be changed into a prime (21012137) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1050597 + ... + 1050616.

Almost surely, 2^21012130 is an apocalyptic number.

21012130 is a deficient number, since it is larger than the sum of its proper divisors (16809722).

21012130 is a wasteful number, since it uses less digits than its factorization.

21012130 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2101220.

The product of its (nonzero) digits is 12, while the sum is 10.

The square root of 21012130 is about 4583.8989953968. The cubic root of 21012130 is about 275.9455276521.

Adding to 21012130 its reverse (3121012), we get a palindrome (24133142).

The spelling of 21012130 in words is "twenty-one million, twelve thousand, one hundred thirty".