21180399251 has 8 divisors (see below), whose sum is σ = 23730374064. Its totient is φ = 18734505120.

The previous prime is 21180399241. The next prime is 21180399259. The reversal of 21180399251 is 15299308112.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21180399251 - 2¹⁰ = 21180398227 is a prime.

It is a super-2 number, since 2×21180399251² (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 = 21180399199 and 21180399208.

It is not an unprimeable number, because it can be changed into a prime (21180399259) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 26019740 + ... + 26020553.

It is an arithmetic number, because the mean of its divisors is an integer number (2966296758).

Almost surely, 2^21180399251 is an apocalyptic number.

21180399251 is a deficient number, since it is larger than the sum of its proper divisors (2549974813).

21180399251 is a wasteful number, since it uses less digits than its factorization.

21180399251 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 52040341.

The product of its (nonzero) digits is 38880, while the sum is 41.

The spelling of 21180399251 in words is "twenty-one billion, one hundred eighty million, three hundred ninety-nine thousand, two hundred fifty-one".