21199467986944 has 135 divisors (see below), whose sum is σ = 45926470691577. Its totient is φ = 9780833746944.

The previous prime is 21199467986909. The next prime is 21199467986951. The reversal of 21199467986944 is 44968976499112.

It is a happy number.

The square root of 21199467986944 is 4604288.

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

It can be written as a sum of positive squares in only one way, i.e., 3136015974400 + 18063452012544 = 1770880^2 + 4250112^2 .

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 7661533849 + ... + 7661536615.

Almost surely, 2^{21199467986944} is an apocalyptic number.

21199467986944 is the 4604288-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21199467986944

21199467986944 is an abundant number, since it is smaller than the sum of its proper divisors (24727002704633).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21199467986944 is an frugal number, since it uses more digits than its factorization.

21199467986944 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5588 (or 2782 counting only the distinct ones).

The product of its digits is 1693052928, while the sum is 79.

The spelling of 21199467986944 in words is "twenty-one trillion, one hundred ninety-nine billion, four hundred sixty-seven million, nine hundred eighty-six thousand, nine hundred forty-four".