2155721710216 has 8 divisors (see below), whose sum is σ = 4041978206670. Its totient is φ = 1077860855104.

The previous prime is 2155721710193. The next prime is 2155721710231. The reversal of 2155721710216 is 6120171275512.

It can be written as a sum of positive squares in only one way, i.e., 1778344934116 + 377376776100 = 1333546^2 + 614310^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 134732606881 + ... + 134732606896.

Almost surely, 2^{2155721710216} is an apocalyptic number.

It is an amenable number.

2155721710216 is a deficient number, since it is larger than the sum of its proper divisors (1886256496454).

2155721710216 is a wasteful number, since it uses less digits than its factorization.

2155721710216 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 269465213783 (or 269465213779 counting only the distinct ones).

The product of its (nonzero) digits is 58800, while the sum is 40.

Adding to 2155721710216 its reverse (6120171275512), we get a palindrome (8275892985728).

The spelling of 2155721710216 in words is "two trillion, one hundred fifty-five billion, seven hundred twenty-one million, seven hundred ten thousand, two hundred sixteen".