1021531109 has 2 divisors, whose sum is σ = 1021531110. Its totient is φ = 1021531108.

The previous prime is 1021531097. The next prime is 1021531117. The reversal of 1021531109 is 9011351201.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 865830625 + 155700484 = 29425^2 + 12478^2 .

It is a cyclic number.

It is not a de Polignac number, because 1021531109 - 2¹⁶ = 1021465573 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1021531129) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 510765554 + 510765555.

It is an arithmetic number, because the mean of its divisors is an integer number (510765555).

Almost surely, 2^1021531109 is an apocalyptic number.

It is an amenable number.

1021531109 is a deficient number, since it is larger than the sum of its proper divisors (1).

1021531109 is an equidigital number, since it uses as much as digits as its factorization.

1021531109 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 270, while the sum is 23.

The square root of 1021531109 is about 31961.4002978593. The cubic root of 1021531109 is about 1007.1261339227.

The spelling of 1021531109 in words is "one billion, twenty-one million, five hundred thirty-one thousand, one hundred nine".