781216020 has 216 divisors, whose sum is σ = 2614254552. Its totient is φ = 188697600.

The previous prime is 781216019. The next prime is 781216031. The reversal of 781216020 is 20612187.

It can be written as a sum of positive squares in 12 ways, for example, as 778744836 + 2471184 = 27906^2 + 1572^2 .

It is a super-2 number, since 2×781216020² = 1220596939809280800, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 1855410 + ... + 1855830.

Almost surely, 2^781216020 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 781216020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1307127276).

781216020 is an abundant number, since it is smaller than the sum of its proper divisors (1833038532).

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

781216020 is a wasteful number, since it uses less digits than its factorization.

781216020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 523 (or 505 counting only the distinct ones).

The product of its (nonzero) digits is 1344, while the sum is 27.

The square root of 781216020 is about 27950.2418594187. The cubic root of 781216020 is about 920.9945215715.

It can be divided in two parts, 7812 and 16020, that added together give a palindrome (23832).

The spelling of 781216020 in words is "seven hundred eighty-one million, two hundred sixteen thousand, twenty".