161725501 has 4 divisors (see below), whose sum is σ = 184829152. Its totient is φ = 138621852.

The previous prime is 161725463. The next prime is 161725517. The reversal of 161725501 is 105527161.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 161725501 - 2⁹ = 161724989 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 161725501.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161725541) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11551815 + ... + 11551828.

It is an arithmetic number, because the mean of its divisors is an integer number (46207288).

Almost surely, 2^161725501 is an apocalyptic number.

It is an amenable number.

161725501 is a deficient number, since it is larger than the sum of its proper divisors (23103651).

161725501 is an equidigital number, since it uses as much as digits as its factorization.

161725501 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23103650.

The product of its (nonzero) digits is 2100, while the sum is 28.

The square root of 161725501 is about 12717.1341504287. The cubic root of 161725501 is about 544.8281039123.

The spelling of 161725501 in words is "one hundred sixty-one million, seven hundred twenty-five thousand, five hundred one".