1540724221 has 4 divisors (see below), whose sum is σ = 1546582752. Its totient is φ = 1534865692.

The previous prime is 1540724197. The next prime is 1540724243. The reversal of 1540724221 is 1224270451.

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 1540724221 - 2¹⁹ = 1540199933 is a prime.

It is a super-3 number, since 3×1540724221³ (a number of 29 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1540724221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1540224221) 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, 2928871 + ... + 2929396.

It is an arithmetic number, because the mean of its divisors is an integer number (386645688).

Almost surely, 2^1540724221 is an apocalyptic number.

It is an amenable number.

1540724221 is a deficient number, since it is larger than the sum of its proper divisors (5858531).

1540724221 is an equidigital number, since it uses as much as digits as its factorization.

1540724221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5858530.

The product of its (nonzero) digits is 4480, while the sum is 28.

The square root of 1540724221 is about 39252.0600860643. The cubic root of 1540724221 is about 1154.9813458754.

Adding to 1540724221 its reverse (1224270451), we get a palindrome (2764994672).

The spelling of 1540724221 in words is "one billion, five hundred forty million, seven hundred twenty-four thousand, two hundred twenty-one".