172020101 has 4 divisors (see below), whose sum is σ = 187658304. Its totient is φ = 156381900.

The previous prime is 172020049. The next prime is 172020109. The reversal of 172020101 is 101020271.

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, and also an emirpimes, since its reverse is a distinct semiprime: 101020271 = 11 ⋅9183661.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-172020101 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (172020109) 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, 7819085 + ... + 7819106.

It is an arithmetic number, because the mean of its divisors is an integer number (46914576).

Almost surely, 2^172020101 is an apocalyptic number.

172020101 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

172020101 is a deficient number, since it is larger than the sum of its proper divisors (15638203).

172020101 is a wasteful number, since it uses less digits than its factorization.

172020101 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15638202.

The product of its (nonzero) digits is 28, while the sum is 14.

The square root of 172020101 is about 13115.6433696559. The cubic root of 172020101 is about 556.1514400808.

Adding to 172020101 its reverse (101020271), we get a palindrome (273040372).

The spelling of 172020101 in words is "one hundred seventy-two million, twenty thousand, one hundred one".