144691991 has 16 divisors (see below), whose sum is σ = 154828800. Its totient is φ = 134977248.

The previous prime is 144691949. The next prime is 144691997. The reversal of 144691991 is 199196441.

It is a cyclic number.

It is not a de Polignac number, because 144691991 - 2¹⁰ = 144690967 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (144691997) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 112490 + ... + 113768.

It is an arithmetic number, because the mean of its divisors is an integer number (9676800).

Almost surely, 2^144691991 is an apocalyptic number.

144691991 is a deficient number, since it is larger than the sum of its proper divisors (10136809).

144691991 is a wasteful number, since it uses less digits than its factorization.

144691991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1438.

The product of its digits is 69984, while the sum is 44.

The square root of 144691991 is about 12028.7984021680. The cubic root of 144691991 is about 524.9865344997.

The spelling of 144691991 in words is "one hundred forty-four million, six hundred ninety-one thousand, nine hundred ninety-one".