21774155531 has 2 divisors, whose sum is σ = 21774155532. Its totient is φ = 21774155530.

The previous prime is 21774155489. The next prime is 21774155549. The reversal of 21774155531 is 13555147712.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21774155531 - 2²⁶ = 21707046667 is a prime.

It is a super-2 number, since 2×21774155531² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21774155551) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10887077765 + 10887077766.

It is an arithmetic number, because the mean of its divisors is an integer number (10887077766).

Almost surely, 2^21774155531 is an apocalyptic number.

21774155531 is a deficient number, since it is larger than the sum of its proper divisors (1).

21774155531 is an equidigital number, since it uses as much as digits as its factorization.

21774155531 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 147000, while the sum is 41.

The spelling of 21774155531 in words is "twenty-one billion, seven hundred seventy-four million, one hundred fifty-five thousand, five hundred thirty-one".