8404493661 has 10 divisors (see below), whose sum is σ = 12554861022. Its totient is φ = 5602995720.

The previous prime is 8404493623. The next prime is 8404493717. The reversal of 8404493661 is 1663944048.

It can be written as a sum of positive squares in only one way, i.e., 6788936025 + 1615557636 = 82395^2 + 40194^2 .

It is not a de Polignac number, because 8404493661 - 2²⁵ = 8370939229 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (8404493621) by changing a digit.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 51879510 + ... + 51879671.

Almost surely, 2^8404493661 is an apocalyptic number.

8404493661 is a gapful number since it is divisible by the number (81) formed by its first and last digit.

It is an amenable number.

8404493661 is a deficient number, since it is larger than the sum of its proper divisors (4150367361).

8404493661 is a wasteful number, since it uses less digits than its factorization.

8404493661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 103759193 (or 103759184 counting only the distinct ones).

The product of its (nonzero) digits is 497664, while the sum is 45.

The square root of 8404493661 is about 91676.0255519402. The cubic root of 8404493661 is about 2033.1551363649.

The spelling of 8404493661 in words is "eight billion, four hundred four million, four hundred ninety-three thousand, six hundred sixty-one".