21980138049 has 105 divisors (see below), whose sum is σ = 36954680853. Its totient is φ = 13065592896.

The previous prime is 21980137999. The next prime is 21980138051. The reversal of 21980138049 is 94083108912.

The square root of 21980138049 is 148257.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 2 ways, for example, as 6821603649 + 15158534400 = 82593^2 + 123120^2 .

It is not a de Polignac number, because 21980138049 - 2⁹ = 21980137537 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21980137995 and 21980138013.

It is not an unprimeable number, because it can be changed into a prime (21980138069) by changing a digit.

It is a polite number, since it can be written in 104 ways as a sum of consecutive naturals, for example, 1156849362 + ... + 1156849380.

Almost surely, 2^21980138049 is an apocalyptic number.

21980138049 is the 148257-th square number.

21980138049 is the 74129-th centered octagonal number.

It is an amenable number.

21980138049 is a deficient number, since it is larger than the sum of its proper divisors (14974542804).

21980138049 is an frugal number, since it uses more digits than its factorization.

21980138049 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 124 (or 39 counting only the distinct ones).

The product of its (nonzero) digits is 124416, while the sum is 45.

The spelling of 21980138049 in words is "twenty-one billion, nine hundred eighty million, one hundred thirty-eight thousand, forty-nine".