190649128781 has 4 divisors (see below), whose sum is σ = 197223236700. Its totient is φ = 184075020864.

The previous prime is 190649128699. The next prime is 190649128799. The reversal of 190649128781 is 187821946091.

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

It can be written as a sum of positive squares in 2 ways, for example, as 156294506281 + 34354622500 = 395341^2 + 185350^2 .

It is a cyclic number.

It is not a de Polignac number, because 190649128781 - 2³⁴ = 173469259597 is a prime.

It is a super-2 number, since 2×190649128781² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (190649178781) 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, 3287053916 + ... + 3287053973.

It is an arithmetic number, because the mean of its divisors is an integer number (49305809175).

Almost surely, 2^190649128781 is an apocalyptic number.

It is an amenable number.

190649128781 is a deficient number, since it is larger than the sum of its proper divisors (6574107919).

190649128781 is an equidigital number, since it uses as much as digits as its factorization.

190649128781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6574107918.

The product of its (nonzero) digits is 1741824, while the sum is 56.

The spelling of 190649128781 in words is "one hundred ninety billion, six hundred forty-nine million, one hundred twenty-eight thousand, seven hundred eighty-one".