81969201 has 6 divisors (see below), whose sum is σ = 118399970. Its totient is φ = 54646128.

The previous prime is 81969187. The next prime is 81969203. The reversal of 81969201 is 10296918.

It can be written as a sum of positive squares in only one way, i.e., 67223601 + 14745600 = 8199^2 + 3840^2 .

It is not a de Polignac number, because 81969201 - 2¹⁰ = 81968177 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81969203) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 4553836 + ... + 4553853.

Almost surely, 2^81969201 is an apocalyptic number.

It is an amenable number.

81969201 is a deficient number, since it is larger than the sum of its proper divisors (36430769).

81969201 is a wasteful number, since it uses less digits than its factorization.

81969201 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9107695 (or 9107692 counting only the distinct ones).

The product of its (nonzero) digits is 7776, while the sum is 36.

The square root of 81969201 is about 9053.6843881372. The cubic root of 81969201 is about 434.3937492105.

The spelling of 81969201 in words is "eighty-one million, nine hundred sixty-nine thousand, two hundred one".