3126820021 has 4 divisors (see below), whose sum is σ = 3367344652. Its totient is φ = 2886295392.

The previous prime is 3126819989. The next prime is 3126820027. The reversal of 3126820021 is 1200286213.

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 2023650225 + 1103169796 = 44985^2 + 33214^2 .

It is a cyclic number.

It is not a de Polignac number, because 3126820021 - 2⁵ = 3126819989 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 (3126820027) 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, 120262296 + ... + 120262321.

It is an arithmetic number, because the mean of its divisors is an integer number (841836163).

Almost surely, 2^3126820021 is an apocalyptic number.

It is an amenable number.

3126820021 is a deficient number, since it is larger than the sum of its proper divisors (240524631).

3126820021 is a wasteful number, since it uses less digits than its factorization.

3126820021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 240524630.

The product of its (nonzero) digits is 1152, while the sum is 25.

The square root of 3126820021 is about 55917.9758306754. The cubic root of 3126820021 is about 1462.2926419532.

The spelling of 3126820021 in words is "three billion, one hundred twenty-six million, eight hundred twenty thousand, twenty-one".