Search a number
-
+
6991531 is a prime number
BaseRepresentation
bin11010101010111010101011
3111011012120121
4122222322223
53242212111
6405504111
7113266321
oct32527253
914135517
106991531
113a45928
122412037
1315aa401
14cddd11
15931871
hex6aaeab

6991531 has 2 divisors, whose sum is σ = 6991532. Its totient is φ = 6991530.

The previous prime is 6991513. The next prime is 6991541. The reversal of 6991531 is 1351996.

Together with previous prime (6991513) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2k-6991531 is a prime.

It is a super-2 number, since 2×69915312 = 97763011447922, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (6991511) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3495765 + 3495766.

It is an arithmetic number, because the mean of its divisors is an integer number (3495766).

Almost surely, 26991531 is an apocalyptic number.

6991531 is the 1183-rd centered decagonal number.

6991531 is a deficient number, since it is larger than the sum of its proper divisors (1).

6991531 is an equidigital number, since it uses as much as digits as its factorization.

6991531 is an evil number, because the sum of its binary digits is even.

The product of its digits is 7290, while the sum is 34.

The square root of 6991531 is about 2644.1503361193. The cubic root of 6991531 is about 191.2159413627.

The spelling of 6991531 in words is "six million, nine hundred ninety-one thousand, five hundred thirty-one".