2129721394 has 8 divisors (see below), whose sum is σ = 3195417708. Its totient is φ = 1064582160.

The previous prime is 2129721389. The next prime is 2129721413. The reversal of 2129721394 is 4931279212.

It can be written as a sum of positive squares in 2 ways, for example, as 2117380225 + 12341169 = 46015^2 + 3513^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a super-2 number, since 2×2129721394² = 9071426432122606472, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 129577 + ... + 145084.

Almost surely, 2^2129721394 is an apocalyptic number.

2129721394 is a deficient number, since it is larger than the sum of its proper divisors (1065696314).

2129721394 is a wasteful number, since it uses less digits than its factorization.

2129721394 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 278540.

The product of its digits is 54432, while the sum is 40.

The square root of 2129721394 is about 46148.9045807157. The cubic root of 2129721394 is about 1286.5922505068.

The spelling of 2129721394 in words is "two billion, one hundred twenty-nine million, seven hundred twenty-one thousand, three hundred ninety-four".