21748678436 has 6 divisors (see below), whose sum is σ = 38060187270. Its totient is φ = 10874339216.

The previous prime is 21748678421. The next prime is 21748678543. The reversal of 21748678436 is 63487684712.

It can be written as a sum of positive squares in only one way, i.e., 15439553536 + 6309124900 = 124256^2 + 79430^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2718584801 + ... + 2718584808.

It is an arithmetic number, because the mean of its divisors is an integer number (6343364545).

Almost surely, 2^21748678436 is an apocalyptic number.

It is an amenable number.

21748678436 is a deficient number, since it is larger than the sum of its proper divisors (16311508834).

21748678436 is a wasteful number, since it uses less digits than its factorization.

21748678436 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5437169613 (or 5437169611 counting only the distinct ones).

The product of its digits is 10838016, while the sum is 56.

The spelling of 21748678436 in words is "twenty-one billion, seven hundred forty-eight million, six hundred seventy-eight thousand, four hundred thirty-six".