91400878387 has 16 divisors (see below), whose sum is σ = 112607014912. Its totient is φ = 72244133280.

The previous prime is 91400878379. The next prime is 91400878411. The reversal of 91400878387 is 78387800419.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 91400878387 - 2³ = 91400878379 is a prime.

It is not an unprimeable number, because it can be changed into a prime (91400878357) 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, 416583 + ... + 596944.

It is an arithmetic number, because the mean of its divisors is an integer number (7037938432).

Almost surely, 2^91400878387 is an apocalyptic number.

91400878387 is a deficient number, since it is larger than the sum of its proper divisors (21206136525).

91400878387 is a wasteful number, since it uses less digits than its factorization.

91400878387 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1014538.

The product of its (nonzero) digits is 2709504, while the sum is 55.

The spelling of 91400878387 in words is "ninety-one billion, four hundred million, eight hundred seventy-eight thousand, three hundred eighty-seven".