21197180651 has 4 divisors (see below), whose sum is σ = 21880960704. Its totient is φ = 20513400600.

The previous prime is 21197180633. The next prime is 21197180659. The reversal of 21197180651 is 15608179112.

It is a happy number.

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

It is not a de Polignac number, because 21197180651 - 2¹⁴ = 21197164267 is a prime.

It is a super-2 number, since 2×21197180651² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21197180599 and 21197180608.

It is not an unprimeable number, because it can be changed into a prime (21197180659) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 341889980 + ... + 341890041.

It is an arithmetic number, because the mean of its divisors is an integer number (5470240176).

Almost surely, 2^21197180651 is an apocalyptic number.

21197180651 is a deficient number, since it is larger than the sum of its proper divisors (683780053).

21197180651 is an equidigital number, since it uses as much as digits as its factorization.

21197180651 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 683780052.

The product of its (nonzero) digits is 30240, while the sum is 41.

The spelling of 21197180651 in words is "twenty-one billion, one hundred ninety-seven million, one hundred eighty thousand, six hundred fifty-one".