2537391721 has 4 divisors (see below), whose sum is σ = 2539664452. Its totient is φ = 2535118992.

The previous prime is 2537391697. The next prime is 2537391733. The reversal of 2537391721 is 1271937352.

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 370023696 + 2167368025 = 19236^2 + 46555^2 .

It is a cyclic number.

It is not a de Polignac number, because 2537391721 - 2²¹ = 2535294569 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2537391751) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1134690 + ... + 1136923.

It is an arithmetic number, because the mean of its divisors is an integer number (634916113).

Almost surely, 2^2537391721 is an apocalyptic number.

It is an amenable number.

2537391721 is a deficient number, since it is larger than the sum of its proper divisors (2272731).

2537391721 is a wasteful number, since it uses less digits than its factorization.

2537391721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2272730.

The product of its digits is 79380, while the sum is 40.

The square root of 2537391721 is about 50372.5294282509. The cubic root of 2537391721 is about 1363.9418010287.

The spelling of 2537391721 in words is "two billion, five hundred thirty-seven million, three hundred ninety-one thousand, seven hundred twenty-one".