661434100540 has 24 divisors (see below), whose sum is σ = 1389032270640. Its totient is φ = 264569705088.

The previous prime is 661434100531. The next prime is 661434100549. The reversal of 661434100540 is 45001434166.

It is an interprime number because it is at equal distance from previous prime (661434100531) and next prime (661434100549).

It is a junction number, because it is equal to n+sod(n) for n = 661434100496 and 661434100505.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661434100549) 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 7 ways as a sum of consecutive naturals, for example, 1401496 + ... + 1813024.

It is an arithmetic number, because the mean of its divisors is an integer number (57876344610).

Almost surely, 2^661434100540 is an apocalyptic number.

It is an amenable number.

661434100540 is an abundant number, since it is smaller than the sum of its proper divisors (727598170100).

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

661434100540 is a wasteful number, since it uses less digits than its factorization.

661434100540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 491901 (or 491899 counting only the distinct ones).

The product of its (nonzero) digits is 34560, while the sum is 34.

The spelling of 661434100540 in words is "six hundred sixty-one billion, four hundred thirty-four million, one hundred thousand, five hundred forty".