163951780649 has 4 divisors (see below), whose sum is σ = 166639514820. Its totient is φ = 161264046480.

The previous prime is 163951780621. The next prime is 163951780661. The reversal of 163951780649 is 946087159361.

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 4305984400 + 159645796249 = 65620^2 + 399557^2 .

It is a cyclic number.

It is not a de Polignac number, because 163951780649 - 2⁸ = 163951780393 is a prime.

It is a super-2 number, since 2×163951780649² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (163951782649) 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, 1343866994 + ... + 1343867115.

It is an arithmetic number, because the mean of its divisors is an integer number (41659878705).

Almost surely, 2^163951780649 is an apocalyptic number.

It is an amenable number.

163951780649 is a deficient number, since it is larger than the sum of its proper divisors (2687734171).

163951780649 is an equidigital number, since it uses as much as digits as its factorization.

163951780649 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2687734170.

The product of its (nonzero) digits is 9797760, while the sum is 59.

The spelling of 163951780649 in words is "one hundred sixty-three billion, nine hundred fifty-one million, seven hundred eighty thousand, six hundred forty-nine".