21125459716 has 9 divisors (see below), whose sum is σ = 36970063221. Its totient is φ = 10562584512.

The previous prime is 21125459689. The next prime is 21125459737. The reversal of 21125459716 is 61795452112.

The square root of 21125459716 is 145346.

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., 9739716100 + 11385743616 = 98690^2 + 106704^2 .

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 254356 + ... + 327028.

Almost surely, 2^21125459716 is an apocalyptic number.

21125459716 is the 145346-th square number.

It is an amenable number.

21125459716 is a deficient number, since it is larger than the sum of its proper divisors (15844603505).

21125459716 is an frugal number, since it uses more digits than its factorization.

21125459716 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 145350 (or 72675 counting only the distinct ones).

The product of its digits is 151200, while the sum is 43.

The spelling of 21125459716 in words is "twenty-one billion, one hundred twenty-five million, four hundred fifty-nine thousand, seven hundred sixteen".