20154421521 has 24 divisors (see below), whose sum is σ = 31446099776. Its totient is φ = 12365226720.

The previous prime is 20154421501. The next prime is 20154421523. The reversal of 20154421521 is 12512445102.

It is a happy number.

20154421521 is a `hidden beast` number, since 201 + 5 + 442 + 15 + 2 + 1 = 666.

It is not a de Polignac number, because 20154421521 - 2⁶ = 20154421457 is a prime.

It is a super-2 number, since 2×20154421521² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (20154421523) 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, 221485 + ... + 298938.

Almost surely, 2^20154421521 is an apocalyptic number.

It is an amenable number.

20154421521 is a deficient number, since it is larger than the sum of its proper divisors (11291678255).

20154421521 is a wasteful number, since it uses less digits than its factorization.

20154421521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 520773 (or 520770 counting only the distinct ones).

The product of its (nonzero) digits is 3200, while the sum is 27.

Adding to 20154421521 its reverse (12512445102), we get a palindrome (32666866623).

The spelling of 20154421521 in words is "twenty billion, one hundred fifty-four million, four hundred twenty-one thousand, five hundred twenty-one".