20772420021 has 6 divisors (see below), whose sum is σ = 30004606710. Its totient is φ = 13848280008.

The previous prime is 20772420013. The next prime is 20772420047. The reversal of 20772420021 is 12002427702.

It can be written as a sum of positive squares in only one way, i.e., 12447864900 + 8324555121 = 111570^2 + 91239^2 .

It is not a de Polignac number, because 20772420021 - 2³ = 20772420013 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20772420061) 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 5 ways as a sum of consecutive naturals, for example, 1154023326 + ... + 1154023343.

It is an arithmetic number, because the mean of its divisors is an integer number (5000767785).

Almost surely, 2^20772420021 is an apocalyptic number.

It is an amenable number.

20772420021 is a deficient number, since it is larger than the sum of its proper divisors (9232186689).

20772420021 is a wasteful number, since it uses less digits than its factorization.

20772420021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2308046675 (or 2308046672 counting only the distinct ones).

The product of its (nonzero) digits is 3136, while the sum is 27.

Adding to 20772420021 its reverse (12002427702), we get a palindrome (32774847723).

The spelling of 20772420021 in words is "twenty billion, seven hundred seventy-two million, four hundred twenty thousand, twenty-one".