201521154421 has 8 divisors (see below), whose sum is σ = 202226056704. Its totient is φ = 200817099600.

The previous prime is 201521154379. The next prime is 201521154427. The reversal of 201521154421 is 124451125102.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 201521154421 - 2¹¹ = 201521152373 is a prime.

It is a super-2 number, since 2×201521154421² (a number of 23 digits) contains 22 as substring.

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 201521154421.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (201521154427) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 266436 + ... + 688498.

It is an arithmetic number, because the mean of its divisors is an integer number (25278257088).

Almost surely, 2^201521154421 is an apocalyptic number.

It is an amenable number.

201521154421 is a deficient number, since it is larger than the sum of its proper divisors (704902283).

201521154421 is a wasteful number, since it uses less digits than its factorization.

201521154421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 423731.

The product of its (nonzero) digits is 3200, while the sum is 28.

Adding to 201521154421 its reverse (124451125102), we get a palindrome (325972279523).

The spelling of 201521154421 in words is "two hundred one billion, five hundred twenty-one million, one hundred fifty-four thousand, four hundred twenty-one".