31123021010020 has 24 divisors (see below), whose sum is σ = 65370939895800. Its totient is φ = 12446809208832.

The previous prime is 31123021009999. The next prime is 31123021010027. The reversal of 31123021010020 is 2001012032113.

It can be written as a sum of positive squares in 4 ways, for example, as 1520999290944 + 29602021719076 = 1233288^2 + 5440774^2 .

It is a junction number, because it is equal to n+sod(n) for n = 31123021009976 and 31123021010003.

It is not an unprimeable number, because it can be changed into a prime (31123021010027) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 149843325 + ... + 150050884.

It is an arithmetic number, because the mean of its divisors is an integer number (2723789162325).

Almost surely, 2^{31123021010020} is an apocalyptic number.

It is an amenable number.

31123021010020 is an abundant number, since it is smaller than the sum of its proper divisors (34247918885780).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

31123021010020 is a wasteful number, since it uses less digits than its factorization.

31123021010020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 299899407 (or 299899405 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 16.

Adding to 31123021010020 its reverse (2001012032113), we get a palindrome (33124033042133).

The spelling of 31123021010020 in words is "thirty-one trillion, one hundred twenty-three billion, twenty-one million, ten thousand, twenty".