161506631 has 16 divisors (see below), whose sum is σ = 199731840. Its totient is φ = 128394720.

The previous prime is 161506627. The next prime is 161506633. The reversal of 161506631 is 136605161.

It is a cyclic number.

It is not a de Polignac number, because 161506631 - 2² = 161506627 is a prime.

It is a super-2 number, since 2×161506631² = 52168783713940322, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 161506594 and 161506603.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161506633) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 27005 + ... + 32438.

It is an arithmetic number, because the mean of its divisors is an integer number (12483240).

Almost surely, 2^161506631 is an apocalyptic number.

161506631 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

161506631 is a deficient number, since it is larger than the sum of its proper divisors (38225209).

161506631 is a wasteful number, since it uses less digits than its factorization.

161506631 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 59486.

The product of its (nonzero) digits is 3240, while the sum is 29.

The square root of 161506631 is about 12708.5259176665. The cubic root of 161506631 is about 544.5822132712.

It can be divided in two parts, 16 and 1506631, that multiplied together give a triangular number (24106096 = T₆₉₄₃).

The spelling of 161506631 in words is "one hundred sixty-one million, five hundred six thousand, six hundred thirty-one".