661884534 has 40 divisors (see below), whose sum is σ = 1530965568. Its totient is φ = 213509520.

The previous prime is 661884533. The next prime is 661884539. The reversal of 661884534 is 435488166.

It is a super-2 number, since 2×661884534² = 876182272696794312, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 661884534.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661884533) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 60877 + ... + 70920.

Almost surely, 2^661884534 is an apocalyptic number.

661884534 is an abundant number, since it is smaller than the sum of its proper divisors (869081034).

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

661884534 is a wasteful number, since it uses less digits than its factorization.

661884534 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 131842 (or 131833 counting only the distinct ones).

The product of its digits is 552960, while the sum is 45.

The square root of 661884534 is about 25727.1167059195. The cubic root of 661884534 is about 871.4866614659.

The spelling of 661884534 in words is "six hundred sixty-one million, eight hundred eighty-four thousand, five hundred thirty-four".