205137010021 has 8 divisors (see below), whose sum is σ = 205741789400. Its totient is φ = 204532328448.

The previous prime is 205137009923. The next prime is 205137010147. The reversal of 205137010021 is 120010731502.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 109967844996 + 95169165025 = 331614^2 + 308495^2 .

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 205137010021 - 2¹⁹ = 205136485733 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 205137009974 and 205137010001.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (205137010621) 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, 8020165 + ... + 8045701.

It is an arithmetic number, because the mean of its divisors is an integer number (25717723675).

Almost surely, 2^205137010021 is an apocalyptic number.

It is an amenable number.

205137010021 is a deficient number, since it is larger than the sum of its proper divisors (604779379).

205137010021 is a wasteful number, since it uses less digits than its factorization.

205137010021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 48903.

The product of its (nonzero) digits is 420, while the sum is 22.

Adding to 205137010021 its reverse (120010731502), we get a palindrome (325147741523).

The spelling of 205137010021 in words is "two hundred five billion, one hundred thirty-seven million, ten thousand, twenty-one".