21582773477 has 2 divisors, whose sum is σ = 21582773478. Its totient is φ = 21582773476.

The previous prime is 21582773383. The next prime is 21582773489. The reversal of 21582773477 is 77437728512.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20404979716 + 1177793761 = 142846^2 + 34319^2 .

It is a cyclic number.

It is not a de Polignac number, because 21582773477 - 2¹⁶ = 21582707941 is a prime.

It is a super-2 number, since 2×21582773477² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21582773077) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10791386738 + 10791386739.

It is an arithmetic number, because the mean of its divisors is an integer number (10791386739).

Almost surely, 2^21582773477 is an apocalyptic number.

It is an amenable number.

21582773477 is a deficient number, since it is larger than the sum of its proper divisors (1).

21582773477 is an equidigital number, since it uses as much as digits as its factorization.

21582773477 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4609920, while the sum is 53.

The spelling of 21582773477 in words is "twenty-one billion, five hundred eighty-two million, seven hundred seventy-three thousand, four hundred seventy-seven".