2840721397 has 4 divisors (see below), whose sum is σ = 2874947040. Its totient is φ = 2806495756.

The previous prime is 2840721379. The next prime is 2840721463. The reversal of 2840721397 is 7931270482.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 2840721397 - 2¹⁹ = 2840197109 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 (2840721337) 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, 17112697 + ... + 17112862.

It is an arithmetic number, because the mean of its divisors is an integer number (718736760).

Almost surely, 2^2840721397 is an apocalyptic number.

It is an amenable number.

2840721397 is a deficient number, since it is larger than the sum of its proper divisors (34225643).

2840721397 is an equidigital number, since it uses as much as digits as its factorization.

2840721397 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 34225642.

The product of its (nonzero) digits is 169344, while the sum is 43.

The square root of 2840721397 is about 53298.4183348812. The cubic root of 2840721397 is about 1416.2596460480.

The spelling of 2840721397 in words is "two billion, eight hundred forty million, seven hundred twenty-one thousand, three hundred ninety-seven".