61115111021 has 4 divisors (see below), whose sum is σ = 61311622944. Its totient is φ = 60918599100.

The previous prime is 61115110963. The next prime is 61115111051. The reversal of 61115111021 is 12011151116.

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 61115111021 - 2¹⁴ = 61115094637 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 61115110984 and 61115111002.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61115111051) 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, 98255495 + ... + 98256116.

It is an arithmetic number, because the mean of its divisors is an integer number (15327905736).

Almost surely, 2^61115111021 is an apocalyptic number.

It is an amenable number.

61115111021 is a deficient number, since it is larger than the sum of its proper divisors (196511923).

61115111021 is a wasteful number, since it uses less digits than its factorization.

61115111021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 196511922.

The product of its (nonzero) digits is 60, while the sum is 20.

Adding to 61115111021 its reverse (12011151116), we get a palindrome (73126262137).

The spelling of 61115111021 in words is "sixty-one billion, one hundred fifteen million, one hundred eleven thousand, twenty-one".