1542545721 has 16 divisors (see below), whose sum is σ = 2286316800. Its totient is φ = 1027885104.

The previous prime is 1542545717. The next prime is 1542545743. The reversal of 1542545721 is 1275452451.

1542545721 is a `hidden beast` number, since 1 + 5 + 42 + 545 + 72 + 1 = 666.

It is not a de Polignac number, because 1542545721 - 2² = 1542545717 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1542544721) 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 15 ways as a sum of consecutive naturals, for example, 51520 + ... + 75758.

It is an arithmetic number, because the mean of its divisors is an integer number (142894800).

Almost surely, 2^1542545721 is an apocalyptic number.

It is an amenable number.

1542545721 is a deficient number, since it is larger than the sum of its proper divisors (743771079).

1542545721 is a wasteful number, since it uses less digits than its factorization.

1542545721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26605 (or 26599 counting only the distinct ones).

The product of its digits is 56000, while the sum is 36.

The square root of 1542545721 is about 39275.2558362132. The cubic root of 1542545721 is about 1155.4363202255.

The spelling of 1542545721 in words is "one billion, five hundred forty-two million, five hundred forty-five thousand, seven hundred twenty-one".