61553236204021 has 4 divisors (see below), whose sum is σ = 61996065241600. Its totient is φ = 61110407166444.

The previous prime is 61553236204001. The next prime is 61553236204027. The reversal of 61553236204021 is 12040263235516.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 61553236204021 - 2¹¹ = 61553236201973 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61553236204027) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 221414518581 + ... + 221414518858.

It is an arithmetic number, because the mean of its divisors is an integer number (15499016310400).

Almost surely, 2^{61553236204021} is an apocalyptic number.

It is an amenable number.

61553236204021 is a deficient number, since it is larger than the sum of its proper divisors (442829037579).

61553236204021 is a wasteful number, since it uses less digits than its factorization.

61553236204021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 442829037578.

The product of its (nonzero) digits is 259200, while the sum is 40.

Adding to 61553236204021 its reverse (12040263235516), we get a palindrome (73593499439537).

The spelling of 61553236204021 in words is "sixty-one trillion, five hundred fifty-three billion, two hundred thirty-six million, two hundred four thousand, twenty-one".