21739347998 has 4 divisors (see below), whose sum is σ = 32609022000. Its totient is φ = 10869673998.

The previous prime is 21739347997. The next prime is 21739348061. The reversal of 21739347998 is 89974393712.

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

It is a self number, because there is not a number n which added to its sum of digits gives 21739347998.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21739347997) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5434836998 + ... + 5434837001.

It is an arithmetic number, because the mean of its divisors is an integer number (8152255500).

Almost surely, 2^21739347998 is an apocalyptic number.

21739347998 is a deficient number, since it is larger than the sum of its proper divisors (10869674002).

21739347998 is a wasteful number, since it uses less digits than its factorization.

21739347998 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10869674001.

The product of its digits is 20575296, while the sum is 62.

The spelling of 21739347998 in words is "twenty-one billion, seven hundred thirty-nine million, three hundred forty-seven thousand, nine hundred ninety-eight".