661565142 has 48 divisors (see below), whose sum is σ = 1724386560. Its totient is φ = 179069616.

The previous prime is 661565137. The next prime is 661565147. The reversal of 661565142 is 241565166.

It is an interprime number because it is at equal distance from previous prime (661565137) and next prime (661565147).

It is a junction number, because it is equal to n+sod(n) for n = 661565097 and 661565106.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661565147) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 135778 + ... + 140565.

It is an arithmetic number, because the mean of its divisors is an integer number (35924720).

Almost surely, 2^661565142 is an apocalyptic number.

661565142 is an abundant number, since it is smaller than the sum of its proper divisors (1062821418).

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

661565142 is a wasteful number, since it uses less digits than its factorization.

661565142 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 276377 (or 276374 counting only the distinct ones).

The product of its digits is 43200, while the sum is 36.

The square root of 661565142 is about 25720.9086542447. The cubic root of 661565142 is about 871.3464604503.

The spelling of 661565142 in words is "six hundred sixty-one million, five hundred sixty-five thousand, one hundred forty-two".