128721545 has 8 divisors (see below), whose sum is σ = 154799424. Its totient is φ = 102754864.

The previous prime is 128721533. The next prime is 128721559. The reversal of 128721545 is 545127821.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 128721545 - 2⁸ = 128721289 is a prime.

It is a super-2 number, since 2×128721545² = 33138472294374050, which contains 22 as substring.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 25229 + ... + 29898.

It is an arithmetic number, because the mean of its divisors is an integer number (19349928).

Almost surely, 2^128721545 is an apocalyptic number.

It is an amenable number.

128721545 is a deficient number, since it is larger than the sum of its proper divisors (26077879).

128721545 is an equidigital number, since it uses as much as digits as its factorization.

128721545 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 55599.

The product of its digits is 22400, while the sum is 35.

The square root of 128721545 is about 11345.5517715094. The cubic root of 128721545 is about 504.9136146065.

The spelling of 128721545 in words is "one hundred twenty-eight million, seven hundred twenty-one thousand, five hundred forty-five".