20311031021 has 8 divisors (see below), whose sum is σ = 20456460024. Its totient is φ = 20165967360.

The previous prime is 20311031009. The next prime is 20311031057. The reversal of 20311031021 is 12013011302.

It can be written as a sum of positive squares in 4 ways, for example, as 1659666121 + 18651364900 = 40739^2 + 136570^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 20311031021 - 2¹⁴ = 20311014637 is a prime.

It is a super-2 number, since 2×20311031021² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20311030987 and 20311031005.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20311030021) 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, 20741 + ... + 202613.

It is an arithmetic number, because the mean of its divisors is an integer number (2557057503).

Almost surely, 2^20311031021 is an apocalyptic number.

It is an amenable number.

20311031021 is a deficient number, since it is larger than the sum of its proper divisors (145429003).

20311031021 is a wasteful number, since it uses less digits than its factorization.

20311031021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 182671.

The product of its (nonzero) digits is 36, while the sum is 14.

Adding to 20311031021 its reverse (12013011302), we get a palindrome (32324042323).

The spelling of 20311031021 in words is "twenty billion, three hundred eleven million, thirty-one thousand, twenty-one".