2021010021 has 10 divisors (see below), whose sum is σ = 3019039782. Its totient is φ = 1347339960.

The previous prime is 2021009999. The next prime is 2021010053. The reversal of 2021010021 is 1200101202.

It can be written as a sum of positive squares in only one way, i.e., 1364933025 + 656076996 = 36945^2 + 25614^2 .

It is not a de Polignac number, because 2021010021 - 2⁵ = 2021009989 is a prime.

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

It is a junction number, because it is equal to n+sod(n) for n = 2021009985 and 2021010012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2021010091) by changing a digit.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 12475290 + ... + 12475451.

Almost surely, 2^2021010021 is an apocalyptic number.

It is an amenable number.

2021010021 is a deficient number, since it is larger than the sum of its proper divisors (998029761).

2021010021 is an equidigital number, since it uses as much as digits as its factorization.

2021010021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24950753 (or 24950744 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 9.

The square root of 2021010021 is about 44955.6450404173. The cubic root of 2021010021 is about 1264.3175186155.

Adding to 2021010021 its reverse (1200101202), we get a palindrome (3221111223).

The spelling of 2021010021 in words is "two billion, twenty-one million, ten thousand, twenty-one".