20515660436661 has 32 divisors (see below), whose sum is σ = 30030920519040. Its totient is φ = 12381869681664.

The previous prime is 20515660436657. The next prime is 20515660436699. The reversal of 20515660436661 is 16663406651502.

It is not a de Polignac number, because 20515660436661 - 2² = 20515660436657 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20515660486661) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 22687416 + ... + 23574353.

It is an arithmetic number, because the mean of its divisors is an integer number (938466266220).

Almost surely, 2^{20515660436661} is an apocalyptic number.

It is an amenable number.

20515660436661 is a deficient number, since it is larger than the sum of its proper divisors (9515260082379).

20515660436661 is a wasteful number, since it uses less digits than its factorization.

20515660436661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 46262005.

The product of its (nonzero) digits is 4665600, while the sum is 51.

The spelling of 20515660436661 in words is "twenty trillion, five hundred fifteen billion, six hundred sixty million, four hundred thirty-six thousand, six hundred sixty-one".