83451991 has 4 divisors (see below), whose sum is σ = 95373712. Its totient is φ = 71530272.

The previous prime is 83451989. The next prime is 83452003. The reversal of 83451991 is 19915438.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 83451991 - 2¹ = 83451989 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (83451791) 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, 5960850 + ... + 5960863.

It is an arithmetic number, because the mean of its divisors is an integer number (23843428).

Almost surely, 2^83451991 is an apocalyptic number.

83451991 is a deficient number, since it is larger than the sum of its proper divisors (11921721).

83451991 is a wasteful number, since it uses less digits than its factorization.

83451991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11921720.

The product of its digits is 38880, while the sum is 40.

The square root of 83451991 is about 9135.2061279426. The cubic root of 83451991 is about 436.9974480875.

It can be divided in two parts, 834 and 51991, that added together give a palindrome (52825).

The spelling of 83451991 in words is "eighty-three million, four hundred fifty-one thousand, nine hundred ninety-one".