2520121666 has 4 divisors (see below), whose sum is σ = 3780182502. Its totient is φ = 1260060832.

The previous prime is 2520121649. The next prime is 2520121679. The reversal of 2520121666 is 6661210252.

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

It can be written as a sum of positive squares in only one way, i.e., 2487116641 + 33005025 = 49871^2 + 5745^2 .

It is a super-2 number, since 2×2520121666² = 12702026422885231112, which contains 22 as substring.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 630030415 + ... + 630030418.

Almost surely, 2^2520121666 is an apocalyptic number.

2520121666 is a deficient number, since it is larger than the sum of its proper divisors (1260060836).

2520121666 is a wasteful number, since it uses less digits than its factorization.

2520121666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1260060835.

The product of its (nonzero) digits is 8640, while the sum is 31.

The square root of 2520121666 is about 50200.8133997847. The cubic root of 2520121666 is about 1360.8403230147.

The spelling of 2520121666 in words is "two billion, five hundred twenty million, one hundred twenty-one thousand, six hundred sixty-six".