225400821 has 16 divisors (see below), whose sum is σ = 308394240. Its totient is φ = 146350080.

The previous prime is 225400817. The next prime is 225400823. The reversal of 225400821 is 128004522.

It is not a de Polignac number, because 225400821 - 2² = 225400817 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 225400791 and 225400800.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (225400823) 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, 93396 + ... + 95778.

It is an arithmetic number, because the mean of its divisors is an integer number (19274640).

Almost surely, 2^225400821 is an apocalyptic number.

It is an amenable number.

225400821 is a deficient number, since it is larger than the sum of its proper divisors (82993419).

225400821 is a wasteful number, since it uses less digits than its factorization.

225400821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3196.

The product of its (nonzero) digits is 1280, while the sum is 24.

The square root of 225400821 is about 15013.3547550173. The cubic root of 225400821 is about 608.5811518663.

The spelling of 225400821 in words is "two hundred twenty-five million, four hundred thousand, eight hundred twenty-one".