2042156521 has 4 divisors (see below), whose sum is σ = 2045931844. Its totient is φ = 2038381200.

The previous prime is 2042156491. The next prime is 2042156549. The reversal of 2042156521 is 1256512402.

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 325297296 + 1716859225 = 18036^2 + 41435^2 .

It is a cyclic number.

It is not a de Polignac number, because 2042156521 - 2⁵ = 2042156489 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 2042156521.

It is not an unprimeable number, because it can be changed into a prime (2042156561) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1886850 + ... + 1887931.

It is an arithmetic number, because the mean of its divisors is an integer number (511482961).

Almost surely, 2^2042156521 is an apocalyptic number.

It is an amenable number.

2042156521 is a deficient number, since it is larger than the sum of its proper divisors (3775323).

2042156521 is an equidigital number, since it uses as much as digits as its factorization.

2042156521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3775322.

The product of its (nonzero) digits is 4800, while the sum is 28.

The square root of 2042156521 is about 45190.2259454409. The cubic root of 2042156521 is about 1268.7118857212.

Adding to 2042156521 its reverse (1256512402), we get a palindrome (3298668923).

The spelling of 2042156521 in words is "two billion, forty-two million, one hundred fifty-six thousand, five hundred twenty-one".