21620751009 has 32 divisors (see below), whose sum is σ = 34655115264. Its totient is φ = 11814223680.

The previous prime is 21620751007. The next prime is 21620751041. The reversal of 21620751009 is 90015702612.

It is not a de Polignac number, because 21620751009 - 2¹ = 21620751007 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21620751007) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 567577 + ... + 604470.

It is an arithmetic number, because the mean of its divisors is an integer number (1082972352).

Almost surely, 2^21620751009 is an apocalyptic number.

It is an amenable number.

21620751009 is a deficient number, since it is larger than the sum of its proper divisors (13034364255).

21620751009 is a wasteful number, since it uses less digits than its factorization.

21620751009 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1172117.

The product of its (nonzero) digits is 7560, while the sum is 33.

The spelling of 21620751009 in words is "twenty-one billion, six hundred twenty million, seven hundred fifty-one thousand, nine".