21549679748 has 6 divisors (see below), whose sum is σ = 37711939566. Its totient is φ = 10774839872.

The previous prime is 21549679733. The next prime is 21549679793. The reversal of 21549679748 is 84797694512.

It can be written as a sum of positive squares in only one way, i.e., 16921326724 + 4628353024 = 130082^2 + 68032^2 .

It is a super-2 number, since 2×21549679748² (a number of 21 digits) contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2693709965 + ... + 2693709972.

It is an arithmetic number, because the mean of its divisors is an integer number (6285323261).

Almost surely, 2^21549679748 is an apocalyptic number.

It is an amenable number.

21549679748 is a deficient number, since it is larger than the sum of its proper divisors (16162259818).

21549679748 is a wasteful number, since it uses less digits than its factorization.

21549679748 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5387419941 (or 5387419939 counting only the distinct ones).

The product of its digits is 30481920, while the sum is 62.

The spelling of 21549679748 in words is "twenty-one billion, five hundred forty-nine million, six hundred seventy-nine thousand, seven hundred forty-eight".