1781409420 has 288 divisors, whose sum is σ = 6491197440. Its totient is φ = 386864640.

The previous prime is 1781409407. The next prime is 1781409431. The reversal of 1781409420 is 249041871.

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

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 2304154 + ... + 2304926.

It is an arithmetic number, because the mean of its divisors is an integer number (22538880).

Almost surely, 2^1781409420 is an apocalyptic number.

1781409420 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1781409420, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3245598720).

1781409420 is an abundant number, since it is smaller than the sum of its proper divisors (4709788020).

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

1781409420 is a wasteful number, since it uses less digits than its factorization.

1781409420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 885 (or 880 counting only the distinct ones).

The product of its (nonzero) digits is 16128, while the sum is 36.

The square root of 1781409420 is about 42206.7461432411. The cubic root of 1781409420 is about 1212.2380589791.

The spelling of 1781409420 in words is "one billion, seven hundred eighty-one million, four hundred nine thousand, four hundred twenty".