4002400121 has 4 divisors (see below), whose sum is σ = 4004624244. Its totient is φ = 4000176000.

The previous prime is 4002400097. The next prime is 4002400123. The reversal of 4002400121 is 1210042004.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 377758096 + 3624642025 = 19436^2 + 60205^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-4002400121 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 4002400096 and 4002400105.

It is not an unprimeable number, because it can be changed into a prime (4002400123) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1109360 + ... + 1112961.

It is an arithmetic number, because the mean of its divisors is an integer number (1001156061).

Almost surely, 2^4002400121 is an apocalyptic number.

It is an amenable number.

4002400121 is a deficient number, since it is larger than the sum of its proper divisors (2224123).

4002400121 is a wasteful number, since it uses less digits than its factorization.

4002400121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2224122.

The product of its (nonzero) digits is 64, while the sum is 14.

The square root of 4002400121 is about 63264.5249804343. The cubic root of 4002400121 is about 1587.7184847036.

Adding to 4002400121 its reverse (1210042004), we get a palindrome (5212442125).

The spelling of 4002400121 in words is "four billion, two million, four hundred thousand, one hundred twenty-one".