2021515151 has 4 divisors (see below), whose sum is σ = 2091222600. Its totient is φ = 1951807704.

The previous prime is 2021515141. The next prime is 2021515157. The reversal of 2021515151 is 1515151202.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1515151202 = 2 ⋅757575601.

It is a cyclic number.

It is not a de Polignac number, because 2021515151 - 2¹⁸ = 2021253007 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2021515157) 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, 34853681 + ... + 34853738.

It is an arithmetic number, because the mean of its divisors is an integer number (522805650).

Almost surely, 2^2021515151 is an apocalyptic number.

2021515151 is a deficient number, since it is larger than the sum of its proper divisors (69707449).

2021515151 is an equidigital number, since it uses as much as digits as its factorization.

2021515151 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 69707448.

The product of its (nonzero) digits is 500, while the sum is 23.

The square root of 2021515151 is about 44961.2627825331. The cubic root of 2021515151 is about 1264.4228440883.

Adding to 2021515151 its reverse (1515151202), we get a palindrome (3536666353).

The spelling of 2021515151 in words is "two billion, twenty-one million, five hundred fifteen thousand, one hundred fifty-one".