215564401 has 24 divisors (see below), whose sum is σ = 240343416. Its totient is φ = 193190400.

The previous prime is 215564399. The next prime is 215564407. The reversal of 215564401 is 104465512.

It can be written as a sum of positive squares in 12 ways, for example, as 9928801 + 205635600 = 3151^2 + 14340^2 .

It is not a de Polignac number, because 215564401 - 2¹ = 215564399 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 215564401.

It is not an unprimeable number, because it can be changed into a prime (215564407) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1245951 + ... + 1246123.

It is an arithmetic number, because the mean of its divisors is an integer number (10014309).

Almost surely, 2^215564401 is an apocalyptic number.

It is an amenable number.

215564401 is a deficient number, since it is larger than the sum of its proper divisors (24779015).

215564401 is a wasteful number, since it uses less digits than its factorization.

215564401 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 373 (or 360 counting only the distinct ones).

The product of its (nonzero) digits is 4800, while the sum is 28.

The square root of 215564401 is about 14682.1115988130. Note that the first 3 decimals coincide. The cubic root of 215564401 is about 599.5963961600.

The spelling of 215564401 in words is "two hundred fifteen million, five hundred sixty-four thousand, four hundred one".