172021406 has 8 divisors (see below), whose sum is σ = 258425640. Its totient is φ = 85879528.

The previous prime is 172021379. The next prime is 172021429. The reversal of 172021406 is 604120271.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 63941 + ... + 66576.

It is an arithmetic number, because the mean of its divisors is an integer number (32303205).

Almost surely, 2^172021406 is an apocalyptic number.

172021406 is a deficient number, since it is larger than the sum of its proper divisors (86404234).

172021406 is a wasteful number, since it uses less digits than its factorization.

172021406 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 131178.

The product of its (nonzero) digits is 672, while the sum is 23.

The square root of 172021406 is about 13115.6931193132. The cubic root of 172021406 is about 556.1528464587.

Adding to 172021406 its reverse (604120271), we get a palindrome (776141677).

The spelling of 172021406 in words is "one hundred seventy-two million, twenty-one thousand, four hundred six".