221215420525 has 24 divisors (see below), whose sum is σ = 305611046784. Its totient is φ = 157460870400.

The previous prime is 221215420519. The next prime is 221215420561. The reversal of 221215420525 is 525024512122.

It is not a de Polignac number, because 221215420525 - 2⁵ = 221215420493 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 8544732 + ... + 8570581.

It is an arithmetic number, because the mean of its divisors is an integer number (12733793616).

Almost surely, 2^221215420525 is an apocalyptic number.

221215420525 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

221215420525 is a deficient number, since it is larger than the sum of its proper divisors (84395626259).

221215420525 is a wasteful number, since it uses less digits than its factorization.

221215420525 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17115381 (or 17115376 counting only the distinct ones).

The product of its (nonzero) digits is 16000, while the sum is 31.

Adding to 221215420525 its reverse (525024512122), we get a palindrome (746239932647).

The spelling of 221215420525 in words is "two hundred twenty-one billion, two hundred fifteen million, four hundred twenty thousand, five hundred twenty-five".