1989666972 has 18 divisors (see below), whose sum is σ = 5029436048. Its totient is φ = 663222312.

The previous prime is 1989666937. The next prime is 1989666977. The reversal of 1989666972 is 2796669891.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (18).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1989666977) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 27634228 + ... + 27634299.

Almost surely, 2^1989666972 is an apocalyptic number.

1989666972 is a gapful number since it is divisible by the number (12) formed by its first and last digit.

It is an amenable number.

1989666972 is an abundant number, since it is smaller than the sum of its proper divisors (3039769076).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1989666972 is a wasteful number, since it uses less digits than its factorization.

1989666972 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 55268537 (or 55268532 counting only the distinct ones).

The product of its digits is 17635968, while the sum is 63.

The square root of 1989666972 is about 44605.6831805096. The cubic root of 1989666972 is about 1257.7475024506.

It can be divided in two parts, 19896 and 66972, that added together give a palindrome (86868).

The spelling of 1989666972 in words is "one billion, nine hundred eighty-nine million, six hundred sixty-six thousand, nine hundred seventy-two".