45156721 has 4 divisors (see below), whose sum is σ = 45556452. Its totient is φ = 44756992.

The previous prime is 45156697. The next prime is 45156737. The reversal of 45156721 is 12765154.

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 11806096 + 33350625 = 3436^2 + 5775^2 .

It is a cyclic number.

It is not a de Polignac number, because 45156721 - 2²³ = 36768113 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (45151721) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 199696 + ... + 199921.

It is an arithmetic number, because the mean of its divisors is an integer number (11389113).

Almost surely, 2^45156721 is an apocalyptic number.

It is an amenable number.

45156721 is a deficient number, since it is larger than the sum of its proper divisors (399731).

45156721 is a wasteful number, since it uses less digits than its factorization.

45156721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 399730.

The product of its digits is 8400, while the sum is 31.

The square root of 45156721 is about 6719.8750732435. The cubic root of 45156721 is about 356.1017704452.

It can be divided in two parts, 4515 and 6721, that added together give a square (11236 = 106²).

The spelling of 45156721 in words is "forty-five million, one hundred fifty-six thousand, seven hundred twenty-one".