21987262837 has 2 divisors, whose sum is σ = 21987262838. Its totient is φ = 21987262836.

The previous prime is 21987262819. The next prime is 21987262853. The reversal of 21987262837 is 73826278912.

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., 19129932721 + 2857330116 = 138311^2 + 53454^2 .

It is a cyclic number.

It is not a de Polignac number, because 21987262837 - 2³¹ = 19839779189 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21987262877) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10993631418 + 10993631419.

It is an arithmetic number, because the mean of its divisors is an integer number (10993631419).

Almost surely, 2^21987262837 is an apocalyptic number.

It is an amenable number.

21987262837 is a deficient number, since it is larger than the sum of its proper divisors (1).

21987262837 is an equidigital number, since it uses as much as digits as its factorization.

21987262837 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4064256, while the sum is 55.

The spelling of 21987262837 in words is "twenty-one billion, nine hundred eighty-seven million, two hundred sixty-two thousand, eight hundred thirty-seven".