21998539967 has 4 divisors (see below), whose sum is σ = 23156357880. Its totient is φ = 20840722056.

The previous prime is 21998539943. The next prime is 21998540017. The reversal of 21998539967 is 76993589912.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21998539967 - 2³² = 17703572671 is a prime.

It is a super-2 number, since 2×21998539967² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21998539897 and 21998539906.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21998539907) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 578908928 + ... + 578908965.

It is an arithmetic number, because the mean of its divisors is an integer number (5789089470).

Almost surely, 2^21998539967 is an apocalyptic number.

21998539967 is a deficient number, since it is larger than the sum of its proper divisors (1157817913).

21998539967 is a wasteful number, since it uses less digits than its factorization.

21998539967 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1157817912.

The product of its digits is 66134880, while the sum is 68.

It can be divided in two parts, 219985 and 39967, that added together give a palindrome (259952).

The spelling of 21998539967 in words is "twenty-one billion, nine hundred ninety-eight million, five hundred thirty-nine thousand, nine hundred sixty-seven".