1621172105 has 48 divisors (see below), whose sum is σ = 2420046720. Its totient is φ = 1035836928.

The previous prime is 1621172099. The next prime is 1621172143. The reversal of 1621172105 is 5012711261.

1621172105 = T₈₁₁₀ + T₈₁₁₁ + ... + T₈₁₅₈.

It is not a de Polignac number, because 1621172105 - 2¹⁴ = 1621155721 is a prime.

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 47 ways as a sum of consecutive naturals, for example, 427106 + ... + 430884.

It is an arithmetic number, because the mean of its divisors is an integer number (50417640).

Almost surely, 2^1621172105 is an apocalyptic number.

It is an amenable number.

1621172105 is a deficient number, since it is larger than the sum of its proper divisors (798874615).

1621172105 is a wasteful number, since it uses less digits than its factorization.

1621172105 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3918 (or 3911 counting only the distinct ones).

The product of its (nonzero) digits is 840, while the sum is 26.

The square root of 1621172105 is about 40263.7815536494. The cubic root of 1621172105 is about 1174.7434731977.

Adding to 1621172105 its reverse (5012711261), we get a palindrome (6633883366).

The spelling of 1621172105 in words is "one billion, six hundred twenty-one million, one hundred seventy-two thousand, one hundred five".