161620394426001 has 135 divisors (see below), whose sum is σ = 274358523227451. Its totient is φ = 91676399627232.

The previous prime is 161620394425993. The next prime is 161620394426009. The reversal of 161620394426001 is 100624493026161.

The square root of 161620394426001 is 12713001.

It is a perfect power (a square), and thus also a powerful number.

161620394426001 is a `hidden beast` number, since 1 + 6 + 1 + 6 + 2 + 0 + 39 + 4 + 4 + 2 + 600 + 1 = 666.

It is an interprime number because it is at equal distance from previous prime (161620394425993) and next prime (161620394426009).

It can be written as a sum of positive squares in only one way, i.e., 158355420084225 + 3264974341776 = 12583935^2 + 1806924^2 .

It is not a de Polignac number, because 161620394426001 - 2³ = 161620394425993 is a prime.

It is a super-2 number, since 2×161620394426001² (a number of 29 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (161620394426009) by changing a digit.

It is a polite number, since it can be written in 134 ways as a sum of consecutive naturals, for example, 368155795740 + ... + 368155796178.

Almost surely, 2^{161620394426001} is an apocalyptic number.

161620394426001 is the 12713001-st square number.

161620394426001 is the 6356501-st centered octagonal number.

It is an amenable number.

161620394426001 is a deficient number, since it is larger than the sum of its proper divisors (112738128801450).

161620394426001 is an frugal number, since it uses more digits than its factorization.

161620394426001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1306 (or 646 counting only the distinct ones).

The product of its (nonzero) digits is 373248, while the sum is 45.

The spelling of 161620394426001 in words is "one hundred sixty-one trillion, six hundred twenty billion, three hundred ninety-four million, four hundred twenty-six thousand, one".