101780891 has 4 divisors (see below), whose sum is σ = 107137800. Its totient is φ = 96423984.

The previous prime is 101780881. The next prime is 101780927. The reversal of 101780891 is 198087101.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-101780891 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (101780801) 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, 2678426 + ... + 2678463.

It is an arithmetic number, because the mean of its divisors is an integer number (26784450).

Almost surely, 2^101780891 is an apocalyptic number.

101780891 is a deficient number, since it is larger than the sum of its proper divisors (5356909).

101780891 is an equidigital number, since it uses as much as digits as its factorization.

101780891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5356908.

The product of its (nonzero) digits is 4032, while the sum is 35.

The square root of 101780891 is about 10088.6515947375. The cubic root of 101780891 is about 466.8980744044.

The spelling of 101780891 in words is "one hundred one million, seven hundred eighty thousand, eight hundred ninety-one".