31000002021 has 16 divisors (see below), whose sum is σ = 45943307200. Its totient is φ = 20658847824.

The previous prime is 31000001987. The next prime is 31000002049. The reversal of 31000002021 is 12020000013.

It is a happy number.

It is not a de Polignac number, because 31000002021 - 2¹¹ = 30999999973 is a prime.

It is a super-2 number, since 2×31000002021² (a number of 22 digits) contains 22 as substring.

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

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 31000001994 and 31000002012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31000002091) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 144106 + ... + 287691.

It is an arithmetic number, because the mean of its divisors is an integer number (2871456700).

Almost surely, 2^31000002021 is an apocalyptic number.

It is an amenable number.

31000002021 is a deficient number, since it is larger than the sum of its proper divisors (14943305179).

31000002021 is a wasteful number, since it uses less digits than its factorization.

31000002021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 434465 (or 434459 counting only the distinct ones).

The product of its (nonzero) digits is 12, while the sum is 9.

Adding to 31000002021 its reverse (12020000013), we get a palindrome (43020002034).

The spelling of 31000002021 in words is "thirty-one billion, two thousand, twenty-one".