10120020021 has 18 divisors (see below), whose sum is σ = 14662792482. Its totient is φ = 6725980800.

The previous prime is 10120020013. The next prime is 10120020023. The reversal of 10120020021 is 12002002101.

It can be written as a sum of positive squares in 3 ways, for example, as 1877922225 + 8242097796 = 43335^2 + 90786^2 .

It is not a de Polignac number, because 10120020021 - 2³ = 10120020013 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a junction number, because it is equal to n+sod(n) for n = 10120019985 and 10120020012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (10120020023) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 1017171 + ... + 1027071.

Almost surely, 2^10120020021 is an apocalyptic number.

It is an amenable number.

10120020021 is a deficient number, since it is larger than the sum of its proper divisors (4542772461).

10120020021 is an frugal number, since it uses more digits than its factorization.

10120020021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10581 (or 10241 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 9.

Adding to 10120020021 its reverse (12002002101), we get a palindrome (22122022122).

The spelling of 10120020021 in words is "ten billion, one hundred twenty million, twenty thousand, twenty-one".