21974567551 has 2 divisors, whose sum is σ = 21974567552. Its totient is φ = 21974567550.

The previous prime is 21974567507. The next prime is 21974567603. The reversal of 21974567551 is 15576547912.

It is an a-pointer prime, because the next prime (21974567603) can be obtained adding 21974567551 to its sum of digits (52).

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21974567551 - 2²⁵ = 21941013119 is a prime.

It is a super-3 number, since 3×21974567551³ (a number of 32 digits) contains 333 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21974597551) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10987283775 + 10987283776.

It is an arithmetic number, because the mean of its divisors is an integer number (10987283776).

Almost surely, 2^21974567551 is an apocalyptic number.

21974567551 is a deficient number, since it is larger than the sum of its proper divisors (1).

21974567551 is an equidigital number, since it uses as much as digits as its factorization.

21974567551 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2646000, while the sum is 52.

It can be divided in two parts, 219745 and 67551, that added together give a square (287296 = 536²).

The spelling of 21974567551 in words is "twenty-one billion, nine hundred seventy-four million, five hundred sixty-seven thousand, five hundred fifty-one".