201521857173 has 16 divisors (see below), whose sum is σ = 330702535296. Its totient is φ = 106297243200.

The previous prime is 201521857169. The next prime is 201521857219. The reversal of 201521857173 is 371758125102.

It is not a de Polignac number, because 201521857173 - 2² = 201521857169 is a prime.

It is a super-2 number, since 2×201521857173² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (201521852173) 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, 369087378 + ... + 369087923.

It is an arithmetic number, because the mean of its divisors is an integer number (20668908456).

Almost surely, 2^201521857173 is an apocalyptic number.

It is an amenable number.

201521857173 is a deficient number, since it is larger than the sum of its proper divisors (129180678123).

201521857173 is a wasteful number, since it uses less digits than its factorization.

201521857173 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 738175324.

The product of its (nonzero) digits is 117600, while the sum is 42.

The spelling of 201521857173 in words is "two hundred one billion, five hundred twenty-one million, eight hundred fifty-seven thousand, one hundred seventy-three".