21251207969 has 8 divisors (see below), whose sum is σ = 22503171240. Its totient is φ = 19999454976.

The previous prime is 21251207959. The next prime is 21251207981. The reversal of 21251207969 is 96970215212.

It can be written as a sum of positive squares in 4 ways, for example, as 6334249744 + 14916958225 = 79588^2 + 122135^2 .

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

It is not a de Polignac number, because 21251207969 - 2⁴ = 21251207953 is a prime.

It is a super-2 number, since 2×21251207969² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21251207959) 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, 186647 + ... + 278099.

It is an arithmetic number, because the mean of its divisors is an integer number (2812896405).

Almost surely, 2^21251207969 is an apocalyptic number.

It is an amenable number.

21251207969 is a deficient number, since it is larger than the sum of its proper divisors (1251963271).

21251207969 is a wasteful number, since it uses less digits than its factorization.

21251207969 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 105139.

The product of its (nonzero) digits is 136080, while the sum is 44.

The spelling of 21251207969 in words is "twenty-one billion, two hundred fifty-one million, two hundred seven thousand, nine hundred sixty-nine".