815121031 has 2 divisors, whose sum is σ = 815121032. Its totient is φ = 815121030.

The previous prime is 815121023. The next prime is 815121053. The reversal of 815121031 is 130121518.

It is an a-pointer prime, because the next prime (815121053) can be obtained adding 815121031 to its sum of digits (22).

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 815121031 - 2³ = 815121023 is a prime.

It is a super-2 number, since 2×815121031² = 1328844590357005922, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 815120993 and 815121011.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (815121001) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 407560515 + 407560516.

It is an arithmetic number, because the mean of its divisors is an integer number (407560516).

Almost surely, 2^815121031 is an apocalyptic number.

815121031 is a deficient number, since it is larger than the sum of its proper divisors (1).

815121031 is an equidigital number, since it uses as much as digits as its factorization.

815121031 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 240, while the sum is 22.

The square root of 815121031 is about 28550.3245340574. The cubic root of 815121031 is about 934.1300996273.

Adding to 815121031 its reverse (130121518), we get a palindrome (945242549).

The spelling of 815121031 in words is "eight hundred fifteen million, one hundred twenty-one thousand, thirty-one".