212728505 has 16 divisors (see below), whose sum is σ = 278769600. Its totient is φ = 154551360.

The previous prime is 212728499. The next prime is 212728507. The reversal of 212728505 is 505827212.

212728505 = T₉₂₂₂ + T₉₂₂₃ + ... + T₉₂₂₆.

It is a happy number.

It is not a de Polignac number, because 212728505 - 2¹⁰ = 212727481 is a prime.

It is not an unprimeable number, because it can be changed into a prime (212728507) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 87851 + ... + 90239.

It is an arithmetic number, because the mean of its divisors is an integer number (17423100).

Almost surely, 2^212728505 is an apocalyptic number.

It is an amenable number.

212728505 is a deficient number, since it is larger than the sum of its proper divisors (66041095).

212728505 is a wasteful number, since it uses less digits than its factorization.

212728505 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4024.

The product of its (nonzero) digits is 11200, while the sum is 32.

The square root of 212728505 is about 14585.2152880923. The cubic root of 212728505 is about 596.9554149305.

The spelling of 212728505 in words is "two hundred twelve million, seven hundred twenty-eight thousand, five hundred five".