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91990391 = 122375217
BaseRepresentation
bin1010111101110…
…10100101110111
320102002121002112
411132322211313
5142022143031
613043401235
72164622363
oct536724567
9212077075
1091990391
1147a20819
122698321b
131609abac
14c3082a3
15812162b
hex57ba977

91990391 has 4 divisors (see below), whose sum is σ = 92066832. Its totient is φ = 91913952.

The previous prime is 91990321. The next prime is 91990411. The reversal of 91990391 is 19309919.

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 91990391 - 210 = 91989367 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 (91990321) 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, 36386 + ... + 38831.

It is an arithmetic number, because the mean of its divisors is an integer number (23016708).

Almost surely, 291990391 is an apocalyptic number.

91990391 is a deficient number, since it is larger than the sum of its proper divisors (76441).

91990391 is a wasteful number, since it uses less digits than its factorization.

91990391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 76440.

The product of its (nonzero) digits is 19683, while the sum is 41.

The square root of 91990391 is about 9591.1621297943. The cubic root of 91990391 is about 451.4200261666.

The spelling of 91990391 in words is "ninety-one million, nine hundred ninety thousand, three hundred ninety-one".

Divisors: 1 1223 75217 91990391