21215249051 has 2 divisors, whose sum is σ = 21215249052. Its totient is φ = 21215249050.

The previous prime is 21215249047. The next prime is 21215249129. The reversal of 21215249051 is 15094251212.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21215249051 - 2² = 21215249047 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21215248999 and 21215249017.

It is not a weakly prime, because it can be changed into another prime (21215249021) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10607624525 + 10607624526.

It is an arithmetic number, because the mean of its divisors is an integer number (10607624526).

Almost surely, 2^21215249051 is an apocalyptic number.

21215249051 is a deficient number, since it is larger than the sum of its proper divisors (1).

21215249051 is an equidigital number, since it uses as much as digits as its factorization.

21215249051 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 7200, while the sum is 32.

The spelling of 21215249051 in words is "twenty-one billion, two hundred fifteen million, two hundred forty-nine thousand, fifty-one".