91439990 has 8 divisors (see below), whose sum is σ = 164592000. Its totient is φ = 36575992.

The previous prime is 91439981. The next prime is 91439993. The reversal of 91439990 is 9993419.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a super-2 number, since 2×91439990² = 16722543542400200, which contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91439993) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4571990 + ... + 4572009.

It is an arithmetic number, because the mean of its divisors is an integer number (20574000).

Almost surely, 2^91439990 is an apocalyptic number.

91439990 is a deficient number, since it is larger than the sum of its proper divisors (73152010).

91439990 is a wasteful number, since it uses less digits than its factorization.

91439990 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9144006.

The product of its (nonzero) digits is 78732, while the sum is 44.

The square root of 91439990 is about 9562.4259474257. The cubic root of 91439990 is about 450.5179057703.

It can be divided in two parts, 91439 and 990, that added together give a palindrome (92429).

The spelling of 91439990 in words is "ninety-one million, four hundred thirty-nine thousand, nine hundred ninety".