1661564 has 6 divisors (see below), whose sum is σ = 2907744. Its totient is φ = 830780.

The previous prime is 1661557. The next prime is 1661567. The reversal of 1661564 is 4651661.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1661567) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 207692 + ... + 207699.

It is an arithmetic number, because the mean of its divisors is an integer number (484624).

2^1661564 is an apocalyptic number.

It is an amenable number.

1661564 is a deficient number, since it is larger than the sum of its proper divisors (1246180).

1661564 is a wasteful number, since it uses less digits than its factorization.

1661564 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 415395 (or 415393 counting only the distinct ones).

The product of its digits is 4320, while the sum is 29.

The square root of 1661564 is about 1289.0166794887. The cubic root of 1661564 is about 118.4419888511.

The spelling of 1661564 in words is "one million, six hundred sixty-one thousand, five hundred sixty-four".