21956274537487 has 2 divisors, whose sum is σ = 21956274537488. Its totient is φ = 21956274537486.

The previous prime is 21956274537479. The next prime is 21956274537497. The reversal of 21956274537487 is 78473547265912.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21956274537487 - 2³ = 21956274537479 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21956274537427) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10978137268743 + 10978137268744.

It is an arithmetic number, because the mean of its divisors is an integer number (10978137268744).

Almost surely, 2^{21956274537487} is an apocalyptic number.

21956274537487 is a deficient number, since it is larger than the sum of its proper divisors (1).

21956274537487 is an equidigital number, since it uses as much as digits as its factorization.

21956274537487 is an evil number, because the sum of its binary digits is even.

The product of its digits is 711244800, while the sum is 70.

The spelling of 21956274537487 in words is "twenty-one trillion, nine hundred fifty-six billion, two hundred seventy-four million, five hundred thirty-seven thousand, four hundred eighty-seven".