2110021561 has 4 divisors (see below), whose sum is σ = 2126636032. Its totient is φ = 2093407092.

The previous prime is 2110021549. The next prime is 2110021583. The reversal of 2110021561 is 1651200112.

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 a de Polignac number, because none of the positive numbers 2^k-2110021561 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2110021591) 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, 8307045 + ... + 8307298.

It is an arithmetic number, because the mean of its divisors is an integer number (531659008).

Almost surely, 2^2110021561 is an apocalyptic number.

It is an amenable number.

2110021561 is a deficient number, since it is larger than the sum of its proper divisors (16614471).

2110021561 is a wasteful number, since it uses less digits than its factorization.

2110021561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16614470.

The product of its (nonzero) digits is 120, while the sum is 19.

The square root of 2110021561 is about 45934.9710024944. The cubic root of 2110021561 is about 1282.6129811411.

Adding to 2110021561 its reverse (1651200112), we get a palindrome (3761221673).

The spelling of 2110021561 in words is "two billion, one hundred ten million, twenty-one thousand, five hundred sixty-one".