21489231789 has 6 divisors (see below), whose sum is σ = 31040001486. Its totient is φ = 14326154520.

The previous prime is 21489231787. The next prime is 21489231823. The reversal of 21489231789 is 98713298412.

It can be written as a sum of positive squares in only one way, i.e., 18269577225 + 3219654564 = 135165^2 + 56742^2 .

It is not a de Polignac number, because 21489231789 - 2¹ = 21489231787 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21489231787) 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, 1193846202 + ... + 1193846219.

It is an arithmetic number, because the mean of its divisors is an integer number (5173333581).

Almost surely, 2^21489231789 is an apocalyptic number.

It is an amenable number.

21489231789 is a deficient number, since it is larger than the sum of its proper divisors (9550769697).

21489231789 is a wasteful number, since it uses less digits than its factorization.

21489231789 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2387692427 (or 2387692424 counting only the distinct ones).

The product of its digits is 1741824, while the sum is 54.

The spelling of 21489231789 in words is "twenty-one billion, four hundred eighty-nine million, two hundred thirty-one thousand, seven hundred eighty-nine".