1540221215 has 24 divisors (see below), whose sum is σ = 2021303808. Its totient is φ = 1126070400.

The previous prime is 1540221203. The next prime is 1540221251. The reversal of 1540221215 is 5121220451.

It is a de Polignac number, because none of the positive numbers 2^k-1540221215 is a prime.

It is a super-2 number, since 2×1540221215² = 4744562782272152450, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 76322 + ... + 94368.

It is an arithmetic number, because the mean of its divisors is an integer number (84220992).

Almost surely, 2^1540221215 is an apocalyptic number.

1540221215 is a deficient number, since it is larger than the sum of its proper divisors (481082593).

1540221215 is a wasteful number, since it uses less digits than its factorization.

1540221215 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18179 (or 18166 counting only the distinct ones).

The product of its (nonzero) digits is 800, while the sum is 23.

The square root of 1540221215 is about 39245.6521795727. The cubic root of 1540221215 is about 1154.8556418345.

Adding to 1540221215 its reverse (5121220451), we get a palindrome (6661441666).

The spelling of 1540221215 in words is "one billion, five hundred forty million, two hundred twenty-one thousand, two hundred fifteen".