521019781489 has 9 divisors (see below), whose sum is σ = 522482664153. Its totient is φ = 519560989332.

The previous prime is 521019781481. The next prime is 521019781553. The reversal of 521019781489 is 984187910125.

The square root of 521019781489 is 721817.

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

It is not a de Polignac number, because 521019781489 - 2³ = 521019781481 is a prime.

It is a super-4 number, since 4×521019781489⁴ (a number of 48 digits) contains 4444 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (521019781481) 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, 334200492 + ... + 334202050.

Almost surely, 2^521019781489 is an apocalyptic number.

521019781489 is the 721817-th square number.

521019781489 is the 360909-th centered octagonal number.

It is an amenable number.

521019781489 is a deficient number, since it is larger than the sum of its proper divisors (1462882664).

521019781489 is an frugal number, since it uses more digits than its factorization.

521019781489 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4044 (or 2022 counting only the distinct ones).

The product of its (nonzero) digits is 1451520, while the sum is 55.

The spelling of 521019781489 in words is "five hundred twenty-one billion, nineteen million, seven hundred eighty-one thousand, four hundred eighty-nine".