121681291 has 16 divisors (see below), whose sum is σ = 132539328. Its totient is φ = 111283200.

The previous prime is 121681279. The next prime is 121681309. The reversal of 121681291 is 192186121.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 121681291 - 2¹⁵ = 121648523 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (121681591) 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 in 15 ways as a sum of consecutive naturals, for example, 87421 + ... + 88801.

It is an arithmetic number, because the mean of its divisors is an integer number (8283708).

Almost surely, 2^121681291 is an apocalyptic number.

121681291 is a deficient number, since it is larger than the sum of its proper divisors (10858037).

121681291 is a wasteful number, since it uses less digits than its factorization.

121681291 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1542.

The product of its digits is 1728, while the sum is 31.

The square root of 121681291 is about 11030.9243039738. The cubic root of 121681291 is about 495.5353063505.

The spelling of 121681291 in words is "one hundred twenty-one million, six hundred eighty-one thousand, two hundred ninety-one".