161551502261 has 8 divisors (see below), whose sum is σ = 164031266880. Its totient is φ = 159089262912.

The previous prime is 161551502251. The next prime is 161551502267. The reversal of 161551502261 is 162205155161.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-161551502261 is a prime.

It is a super-2 number, since 2×161551502261² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161551502267) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4362740 + ... + 4399613.

It is an arithmetic number, because the mean of its divisors is an integer number (20503908360).

Almost surely, 2^161551502261 is an apocalyptic number.

It is an amenable number.

161551502261 is a deficient number, since it is larger than the sum of its proper divisors (2479764619).

161551502261 is a wasteful number, since it uses less digits than its factorization.

161551502261 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8762635.

The product of its (nonzero) digits is 18000, while the sum is 35.

The spelling of 161551502261 in words is "one hundred sixty-one billion, five hundred fifty-one million, five hundred two thousand, two hundred sixty-one".