780061670521 has 9 divisors (see below), whose sum is σ = 907425869871. Its totient is φ = 668618989752.

The previous prime is 780061670491. The next prime is 780061670539. The reversal of 780061670521 is 125076160087.

The square root of 780061670521 is 883211.

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., 154956386025 + 625105284496 = 393645^2 + 790636^2 .

It is not a de Polignac number, because 780061670521 - 2⁷ = 780061670393 is a prime.

It is a super-2 number, since 2×780061670521² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (780061670821) 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, 6119391 + ... + 6245563.

Almost surely, 2^780061670521 is an apocalyptic number.

780061670521 is the 883211-st square number.

780061670521 is the 441606-th centered octagonal number.

It is an amenable number.

780061670521 is a deficient number, since it is larger than the sum of its proper divisors (127364199350).

780061670521 is an frugal number, since it uses more digits than its factorization.

780061670521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 252360 (or 126180 counting only the distinct ones).

The product of its (nonzero) digits is 141120, while the sum is 43.

The spelling of 780061670521 in words is "seven hundred eighty billion, sixty-one million, six hundred seventy thousand, five hundred twenty-one".