78641671521 has 32 divisors (see below), whose sum is σ = 120826368000. Its totient is φ = 44567772480.

The previous prime is 78641671477. The next prime is 78641671547. The reversal of 78641671521 is 12517614687.

It is not a de Polignac number, because 78641671521 - 2¹¹ = 78641669473 is a prime.

It is not an unprimeable number, because it can be changed into a prime (78641671321) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1269415 + ... + 1329923.

It is an arithmetic number, because the mean of its divisors is an integer number (3775824000).

Almost surely, 2^78641671521 is an apocalyptic number.

It is an amenable number.

78641671521 is a deficient number, since it is larger than the sum of its proper divisors (42184696479).

78641671521 is a wasteful number, since it uses less digits than its factorization.

78641671521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 61029.

The product of its digits is 564480, while the sum is 48.

The spelling of 78641671521 in words is "seventy-eight billion, six hundred forty-one million, six hundred seventy-one thousand, five hundred twenty-one".