21115577344 has 99 divisors (see below), whose sum is σ = 44736245427. Its totient is φ = 9960265728.

The previous prime is 21115577339. The next prime is 21115577347. The reversal of 21115577344 is 44377551112.

The square root of 21115577344 is 145312.

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

It is a junction number, because it is equal to n+sod(n) for n = 21115577297 and 21115577306.

It is not an unprimeable number, because it can be changed into a prime (21115577347) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 88349577 + ... + 88349815.

Almost surely, 2^21115577344 is an apocalyptic number.

21115577344 is the 145312-nd square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21115577344

21115577344 is an abundant number, since it is smaller than the sum of its proper divisors (23620668083).

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

21115577344 is an frugal number, since it uses more digits than its factorization.

21115577344 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 536 (or 260 counting only the distinct ones).

The product of its digits is 117600, while the sum is 40.

The spelling of 21115577344 in words is "twenty-one billion, one hundred fifteen million, five hundred seventy-seven thousand, three hundred forty-four".