21251651733 has 96 divisors (see below), whose sum is σ = 35451561600. Its totient is φ = 12172672512.

The previous prime is 21251651731. The next prime is 21251651761. The reversal of 21251651733 is 33715615212.

21251651733 is a `hidden beast` number, since 2 + 125 + 16 + 517 + 3 + 3 = 666.

It is not a de Polignac number, because 21251651733 - 2¹ = 21251651731 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21251651731) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 10608910 + ... + 10610912.

It is an arithmetic number, because the mean of its divisors is an integer number (369287100).

Almost surely, 2^21251651733 is an apocalyptic number.

It is an amenable number.

21251651733 is a deficient number, since it is larger than the sum of its proper divisors (14199909867).

21251651733 is a wasteful number, since it uses less digits than its factorization.

21251651733 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2163 (or 2160 counting only the distinct ones).

The product of its digits is 37800, while the sum is 36.

The spelling of 21251651733 in words is "twenty-one billion, two hundred fifty-one million, six hundred fifty-one thousand, seven hundred thirty-three".