2124991621 has 4 divisors (see below), whose sum is σ = 2146031244. Its totient is φ = 2103952000.

The previous prime is 2124991579. The next prime is 2124991633. The reversal of 2124991621 is 1261994212.

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 1175735521 + 949256100 = 34289^2 + 30810^2 .

It is a cyclic number.

It is not a de Polignac number, because 2124991621 - 2⁷ = 2124991493 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2124991681) 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, 10519660 + ... + 10519861.

It is an arithmetic number, because the mean of its divisors is an integer number (536507811).

Almost surely, 2^2124991621 is an apocalyptic number.

It is an amenable number.

2124991621 is a deficient number, since it is larger than the sum of its proper divisors (21039623).

2124991621 is a wasteful number, since it uses less digits than its factorization.

2124991621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21039622.

The product of its digits is 15552, while the sum is 37.

The square root of 2124991621 is about 46097.6314033595. The cubic root of 2124991621 is about 1285.6391055411.

The spelling of 2124991621 in words is "two billion, one hundred twenty-four million, nine hundred ninety-one thousand, six hundred twenty-one".