661211510065102 has 16 divisors (see below), whose sum is σ = 992308728557952. Its totient is φ = 330441971862240.

The previous prime is 661211510065079. The next prime is 661211510065111. The reversal of 661211510065102 is 201560015112166.

It is a super-2 number, since 2×661211510065102² (a number of 30 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 25340428 + ... + 44323360.

It is an arithmetic number, because the mean of its divisors is an integer number (62019295534872).

Almost surely, 2^{661211510065102} is an apocalyptic number.

661211510065102 is a deficient number, since it is larger than the sum of its proper divisors (331097218492850).

661211510065102 is a wasteful number, since it uses less digits than its factorization.

661211510065102 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18991563.

The product of its (nonzero) digits is 21600, while the sum is 37.

Adding to 661211510065102 its reverse (201560015112166), we get a palindrome (862771525177268).

The spelling of 661211510065102 in words is "six hundred sixty-one trillion, two hundred eleven billion, five hundred ten million, sixty-five thousand, one hundred two".