17121420 has 72 divisors (see below), whose sum is σ = 52686816. Its totient is φ = 4499712.

The previous prime is 17121409. The next prime is 17121427. The reversal of 17121420 is 2412171.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 17121393 and 17121402.

It is not an unprimeable number, because it can be changed into a prime (17121427) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 12489 + ... + 13791.

Almost surely, 2^17121420 is an apocalyptic number.

17121420 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 17121420, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26343408).

17121420 is an abundant number, since it is smaller than the sum of its proper divisors (35565396).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

17121420 is a wasteful number, since it uses less digits than its factorization.

17121420 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1391 (or 1386 counting only the distinct ones).

The product of its (nonzero) digits is 112, while the sum is 18.

The square root of 17121420 is about 4137.8037652842. The cubic root of 17121420 is about 257.7388740724.

Adding to 17121420 its reverse (2412171), we get a palindrome (19533591).

The spelling of 17121420 in words is "seventeen million, one hundred twenty-one thousand, four hundred twenty".