163725661 has 16 divisors (see below), whose sum is σ = 187319808. Its totient is φ = 141649200.

The previous prime is 163725659. The next prime is 163725697. The reversal of 163725661 is 166527361.

It is not a de Polignac number, because 163725661 - 2¹ = 163725659 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 163725661.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (163725761) 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, 51850 + ... + 54916.

It is an arithmetic number, because the mean of its divisors is an integer number (11707488).

Almost surely, 2^163725661 is an apocalyptic number.

163725661 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

163725661 is the 6840-th centered heptagonal number.

It is an amenable number.

163725661 is a deficient number, since it is larger than the sum of its proper divisors (23594147).

163725661 is a wasteful number, since it uses less digits than its factorization.

163725661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3312.

The product of its digits is 45360, while the sum is 37.

The square root of 163725661 is about 12795.5328533047. The cubic root of 163725661 is about 547.0649836402.

The spelling of 163725661 in words is "one hundred sixty-three million, seven hundred twenty-five thousand, six hundred sixty-one".