91778401 has 16 divisors (see below), whose sum is σ = 108295488. Its totient is φ = 76680000.

The previous prime is 91778399. The next prime is 91778411. The reversal of 91778401 is 10487719.

It is a cyclic number.

It is not a de Polignac number, because 91778401 - 2¹ = 91778399 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (91778411) 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, 34615 + ... + 37171.

It is an arithmetic number, because the mean of its divisors is an integer number (6768468).

Almost surely, 2^91778401 is an apocalyptic number.

It is an amenable number.

91778401 is a deficient number, since it is larger than the sum of its proper divisors (16517087).

91778401 is a wasteful number, since it uses less digits than its factorization.

91778401 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2832.

The product of its (nonzero) digits is 14112, while the sum is 37.

The square root of 91778401 is about 9580.1044357564. The cubic root of 91778401 is about 451.0729966751.

It can be divided in two parts, 9177 and 8401, that added together give a triangular number (17578 = T₁₈₇).

The spelling of 91778401 in words is "ninety-one million, seven hundred seventy-eight thousand, four hundred one".