1217420928 has 160 divisors (see below), whose sum is σ = 3748882500. Its totient is φ = 391716864.

The previous prime is 1217420917. The next prime is 1217420969. The reversal of 1217420928 is 8290247121.

It can be written as a sum of positive squares in 2 ways, for example, as 1199375424 + 18045504 = 34632^2 + 4248^2 .

It is a super-2 number, since 2×1217420928² = 2964227431864762368, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 1217420892 and 1217420901.

It is an unprimeable number.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 298648 + ... + 302696.

Almost surely, 2^1217420928 is an apocalyptic number.

1217420928 is a gapful number since it is divisible by the number (18) 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 1217420928, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1874441250).

1217420928 is an abundant number, since it is smaller than the sum of its proper divisors (2531461572).

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

1217420928 is an equidigital number, since it uses as much as digits as its factorization.

1217420928 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4104 (or 4083 counting only the distinct ones).

The product of its (nonzero) digits is 16128, while the sum is 36.

The square root of 1217420928 is about 34891.5595524190. The cubic root of 1217420928 is about 1067.7762439967.

The spelling of 1217420928 in words is "one billion, two hundred seventeen million, four hundred twenty thousand, nine hundred twenty-eight".