2121017920 has 336 divisors, whose sum is σ = 6363949680. Its totient is φ = 668860416.

The previous prime is 2121017909. The next prime is 2121017947. The reversal of 2121017920 is 297101212.

It can be written as a sum of positive squares in 8 ways, for example, as 93857344 + 2027160576 = 9688^2 + 45024^2 .

It is a super-2 number, since 2×2121017920² = 8997434033922252800, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 19458826 + ... + 19458934.

Almost surely, 2^2121017920 is an apocalyptic number.

2121017920 is a gapful number since it is divisible by the number (20) 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 2121017920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3181974840).

2121017920 is an abundant number, since it is smaller than the sum of its proper divisors (4242931760).

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

2121017920 is a wasteful number, since it uses less digits than its factorization.

2121017920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 230 (or 213 counting only the distinct ones).

The product of its (nonzero) digits is 504, while the sum is 25.

The square root of 2121017920 is about 46054.5103111519. The cubic root of 2121017920 is about 1284.8372305148.

The spelling of 2121017920 in words is "two billion, one hundred twenty-one million, seventeen thousand, nine hundred twenty".