201521154218 has 4 divisors (see below), whose sum is σ = 302281731330. Its totient is φ = 100760577108.

The previous prime is 201521154217. The next prime is 201521154221. The reversal of 201521154218 is 812451125102.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 201517494649 + 3659569 = 448907^2 + 1913^2 .

It is a super-2 number, since 2×201521154218² (a number of 23 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (201521154217) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 50380288553 + ... + 50380288556.

Almost surely, 2^201521154218 is an apocalyptic number.

201521154218 is a deficient number, since it is larger than the sum of its proper divisors (100760577112).

201521154218 is a wasteful number, since it uses less digits than its factorization.

201521154218 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 100760577111.

The product of its (nonzero) digits is 6400, while the sum is 32.

The spelling of 201521154218 in words is "two hundred one billion, five hundred twenty-one million, one hundred fifty-four thousand, two hundred eighteen".