9778021641 has 6 divisors (see below), whose sum is σ = 14123809050. Its totient is φ = 6518681088.

The previous prime is 9778021633. The next prime is 9778021663. The reversal of 9778021641 is 1461208779.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 9716242041 + 61779600 = 98571^2 + 7860^2 .

It is not a de Polignac number, because 9778021641 - 2³ = 9778021633 is a prime.

It is a super-4 number, since 4×9778021641⁴ (a number of 41 digits) contains 4444 as substring.

It is not an unprimeable number, because it can be changed into a prime (9778021621) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 543223416 + ... + 543223433.

It is an arithmetic number, because the mean of its divisors is an integer number (2353968175).

Almost surely, 2^9778021641 is an apocalyptic number.

It is an amenable number.

9778021641 is a deficient number, since it is larger than the sum of its proper divisors (4345787409).

9778021641 is a wasteful number, since it uses less digits than its factorization.

9778021641 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1086446855 (or 1086446852 counting only the distinct ones).

The product of its (nonzero) digits is 169344, while the sum is 45.

The square root of 9778021641 is about 98883.8795810520. The cubic root of 9778021641 is about 2138.3739971144.

The spelling of 9778021641 in words is "nine billion, seven hundred seventy-eight million, twenty-one thousand, six hundred forty-one".