2151085321561 has 6 divisors (see below), whose sum is σ = 2364416097386. Its totient is φ = 1955532110400.

The previous prime is 2151085321523. The next prime is 2151085321607. The reversal of 2151085321561 is 1651235801512.

It can be written as a sum of positive squares in only one way, i.e., 1208088955161 + 942996366400 = 1099131^2 + 971080^2 .

It is not a de Polignac number, because 2151085321561 - 2¹⁷ = 2151085190489 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2151085321061) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 8888782200 + ... + 8888782441.

Almost surely, 2^{2151085321561} is an apocalyptic number.

It is an amenable number.

2151085321561 is a deficient number, since it is larger than the sum of its proper divisors (213330775825).

2151085321561 is a wasteful number, since it uses less digits than its factorization.

2151085321561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17777564663 (or 17777564652 counting only the distinct ones).

The product of its (nonzero) digits is 72000, while the sum is 40.

The spelling of 2151085321561 in words is "two trillion, one hundred fifty-one billion, eighty-five million, three hundred twenty-one thousand, five hundred sixty-one".