611556221651 has 4 divisors (see below), whose sum is σ = 621921581400. Its totient is φ = 601190861904.

The previous prime is 611556221629. The next prime is 611556221657. The reversal of 611556221651 is 156122655116.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-611556221651 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 611556221599 and 611556221608.

It is not an unprimeable number, because it can be changed into a prime (611556221657) 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, 5182679786 + ... + 5182679903.

It is an arithmetic number, because the mean of its divisors is an integer number (155480395350).

Almost surely, 2^611556221651 is an apocalyptic number.

611556221651 is a deficient number, since it is larger than the sum of its proper divisors (10365359749).

611556221651 is a wasteful number, since it uses less digits than its factorization.

611556221651 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10365359748.

The product of its digits is 108000, while the sum is 41.

Adding to 611556221651 its reverse (156122655116), we get a palindrome (767678876767).

The spelling of 611556221651 in words is "six hundred eleven billion, five hundred fifty-six million, two hundred twenty-one thousand, six hundred fifty-one".