21651273777819 has 32 divisors (see below), whose sum is σ = 34923809733120. Its totient is φ = 11667727314432.

The previous prime is 21651273777817. The next prime is 21651273777839. The reversal of 21651273777819 is 91877737215612.

It is not a de Polignac number, because 21651273777819 - 2¹ = 21651273777817 is a prime.

It is a super-2 number, since 2×21651273777819² (a number of 27 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21651273777819.

It is not an unprimeable number, because it can be changed into a prime (21651273777817) 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, 413371182 + ... + 413423555.

It is an arithmetic number, because the mean of its divisors is an integer number (1091369054160).

Almost surely, 2^{21651273777819} is an apocalyptic number.

21651273777819 is a gapful number since it is divisible by the number (29) formed by its first and last digit.

21651273777819 is a deficient number, since it is larger than the sum of its proper divisors (13272535955301).

21651273777819 is a wasteful number, since it uses less digits than its factorization.

21651273777819 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 826794819.

The product of its digits is 62233920, while the sum is 66.

The spelling of 21651273777819 in words is "twenty-one trillion, six hundred fifty-one billion, two hundred seventy-three million, seven hundred seventy-seven thousand, eight hundred nineteen".