1781451216 has 60 divisors (see below), whose sum is σ = 5278866372. Its totient is φ = 558885888.

The previous prime is 1781451167. The next prime is 1781451253. The reversal of 1781451216 is 6121541871.

It can be written as a sum of positive squares in 2 ways, for example, as 986211216 + 795240000 = 31404^2 + 28200^2 .

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 361411 + ... + 366306.

Almost surely, 2^1781451216 is an apocalyptic number.

1781451216 is a gapful number since it is divisible by the number (16) formed by its first and last digit.

It is an amenable number.

1781451216 is an abundant number, since it is smaller than the sum of its proper divisors (3497415156).

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

1781451216 is a wasteful number, since it uses less digits than its factorization.

1781451216 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 727748 (or 727739 counting only the distinct ones).

The product of its digits is 13440, while the sum is 36.

The square root of 1781451216 is about 42207.2412744543. The cubic root of 1781451216 is about 1212.2475395445.

The spelling of 1781451216 in words is "one billion, seven hundred eighty-one million, four hundred fifty-one thousand, two hundred sixteen".