81190969 has 2 divisors, whose sum is σ = 81190970. Its totient is φ = 81190968.

The previous prime is 81190961. The next prime is 81191003. The reversal of 81190969 is 96909118.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 81000000 + 190969 = 9000^2 + 437^2 .

It is a cyclic number.

It is not a de Polignac number, because 81190969 - 2³ = 81190961 is a prime.

It is a super-2 number, since 2×81190969² = 13183946894317922, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (81190961) 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, 40595484 + 40595485.

It is an arithmetic number, because the mean of its divisors is an integer number (40595485).

Almost surely, 2^81190969 is an apocalyptic number.

It is an amenable number.

81190969 is a deficient number, since it is larger than the sum of its proper divisors (1).

81190969 is an equidigital number, since it uses as much as digits as its factorization.

81190969 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 34992, while the sum is 43.

The square root of 81190969 is about 9010.6031429644. The cubic root of 81190969 is about 433.0146350306.

It can be divided in two parts, 81 and 190969, that multiplied together give a square (15468489 = 3933²).

The spelling of 81190969 in words is "eighty-one million, one hundred ninety thousand, nine hundred sixty-nine".