989471921661 has 24 divisors (see below), whose sum is σ = 1435814567616. Its totient is φ = 656614719360.

The previous prime is 989471921629. The next prime is 989471921663. The reversal of 989471921661 is 166129174989.

989471921661 is a `hidden beast` number, since 9 + 8 + 9 + 471 + 92 + 16 + 61 = 666.

It is not a de Polignac number, because 989471921661 - 2⁵ = 989471921629 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (989471921663) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 4763376 + ... + 4966758.

It is an arithmetic number, because the mean of its divisors is an integer number (59825606984).

Almost surely, 2^989471921661 is an apocalyptic number.

It is an amenable number.

989471921661 is a deficient number, since it is larger than the sum of its proper divisors (446342645955).

989471921661 is a wasteful number, since it uses less digits than its factorization.

989471921661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 205873 (or 205870 counting only the distinct ones).

The product of its digits is 11757312, while the sum is 63.

The spelling of 989471921661 in words is "nine hundred eighty-nine billion, four hundred seventy-one million, nine hundred twenty-one thousand, six hundred sixty-one".