2021420645 has 4 divisors (see below), whose sum is σ = 2425704780. Its totient is φ = 1617136512.

The previous prime is 2021420617. The next prime is 2021420693. The reversal of 2021420645 is 5460241202.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 1034329921 + 987090724 = 32161^2 + 31418^2 .

It is a cyclic number.

It is not a de Polignac number, because 2021420645 - 2¹⁸ = 2021158501 is a prime.

It is a super-2 number, since 2×2021420645² = 8172282848064432050, which contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 202142060 + ... + 202142069.

It is an arithmetic number, because the mean of its divisors is an integer number (606426195).

Almost surely, 2^2021420645 is an apocalyptic number.

It is an amenable number.

2021420645 is a deficient number, since it is larger than the sum of its proper divisors (404284135).

2021420645 is an equidigital number, since it uses as much as digits as its factorization.

2021420645 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 404284134.

The product of its (nonzero) digits is 3840, while the sum is 26.

The square root of 2021420645 is about 44960.2117988784. The cubic root of 2021420645 is about 1264.4031398239.

Adding to 2021420645 its reverse (5460241202), we get a palindrome (7481661847).

The spelling of 2021420645 in words is "two billion, twenty-one million, four hundred twenty thousand, six hundred forty-five".