201781161615 has 64 divisors (see below), whose sum is σ = 373012231680. Its totient is φ = 92054999040.

The previous prime is 201781161613. The next prime is 201781161623. The reversal of 201781161615 is 516161187102.

It is a happy number.

It is not a de Polignac number, because 201781161615 - 2¹ = 201781161613 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (201781161613) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 16086016 + ... + 16098554.

It is an arithmetic number, because the mean of its divisors is an integer number (5828316120).

Almost surely, 2^201781161615 is an apocalyptic number.

201781161615 is a deficient number, since it is larger than the sum of its proper divisors (171231070065).

201781161615 is a wasteful number, since it uses less digits than its factorization.

201781161615 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18312.

The product of its (nonzero) digits is 20160, while the sum is 39.

The spelling of 201781161615 in words is "two hundred one billion, seven hundred eighty-one million, one hundred sixty-one thousand, six hundred fifteen".