21115661060365 has 16 divisors (see below), whose sum is σ = 25346752244352. Its totient is φ = 16887223450944.

The previous prime is 21115661060357. The next prime is 21115661060399. The reversal of 21115661060365 is 56306016651112.

It is a cyclic number.

It is not a de Polignac number, because 21115661060365 - 2³ = 21115661060357 is a prime.

It is a super-2 number, since 2×21115661060365² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 455772832 + ... + 455819158.

It is an arithmetic number, because the mean of its divisors is an integer number (1584172015272).

Almost surely, 2^{21115661060365} is an apocalyptic number.

It is an amenable number.

21115661060365 is a deficient number, since it is larger than the sum of its proper divisors (4231091183987).

21115661060365 is a wasteful number, since it uses less digits than its factorization.

21115661060365 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 72996.

The product of its (nonzero) digits is 194400, while the sum is 43.

The spelling of 21115661060365 in words is "twenty-one trillion, one hundred fifteen billion, six hundred sixty-one million, sixty thousand, three hundred sixty-five".