1578457661 has 16 divisors (see below), whose sum is σ = 1816028160. Its totient is φ = 1356853680.

The previous prime is 1578457637. The next prime is 1578457663. The reversal of 1578457661 is 1667548751.

It is a happy number.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1578457661 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1578457663) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 107420 + ... + 121226.

It is an arithmetic number, because the mean of its divisors is an integer number (113501760).

Almost surely, 2^1578457661 is an apocalyptic number.

1578457661 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1578457661 is a deficient number, since it is larger than the sum of its proper divisors (237570499).

1578457661 is a wasteful number, since it uses less digits than its factorization.

1578457661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14384.

The product of its digits is 1411200, while the sum is 50.

The square root of 1578457661 is about 39729.8082175084. The cubic root of 1578457661 is about 1164.3341774314.

The spelling of 1578457661 in words is "one billion, five hundred seventy-eight million, four hundred fifty-seven thousand, six hundred sixty-one".