661220411535 has 96 divisors (see below), whose sum is σ = 1204206981120. Its totient is φ = 334994558976.

The previous prime is 661220411503. The next prime is 661220411543. The reversal of 661220411535 is 535114022166.

661220411535 is a `hidden beast` number, since 6 + 61 + 2 + 20 + 41 + 1 + 535 = 666.

It is not a de Polignac number, because 661220411535 - 2⁵ = 661220411503 is a prime.

It is a super-2 number, since 2×661220411535² (a number of 24 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 661220411535.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 131636034 + ... + 131641056.

It is an arithmetic number, because the mean of its divisors is an integer number (12543822720).

Almost surely, 2^661220411535 is an apocalyptic number.

661220411535 is a deficient number, since it is larger than the sum of its proper divisors (542986569585).

661220411535 is a wasteful number, since it uses less digits than its factorization.

661220411535 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5909 (or 5906 counting only the distinct ones).

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

The spelling of 661220411535 in words is "six hundred sixty-one billion, two hundred twenty million, four hundred eleven thousand, five hundred thirty-five".