2638661381 has 2 divisors, whose sum is σ = 2638661382. Its totient is φ = 2638661380.

The previous prime is 2638661369. The next prime is 2638661411. The reversal of 2638661381 is 1831668362.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1602400900 + 1036260481 = 40030^2 + 32191^2 .

It is a cyclic number.

It is not a de Polignac number, because 2638661381 - 2¹⁰ = 2638660357 is a prime.

It is a super-2 number, since 2×2638661381² = 13925067767161654322, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2638661321) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1319330690 + 1319330691.

It is an arithmetic number, because the mean of its divisors is an integer number (1319330691).

Almost surely, 2^2638661381 is an apocalyptic number.

It is an amenable number.

2638661381 is a deficient number, since it is larger than the sum of its proper divisors (1).

2638661381 is an equidigital number, since it uses as much as digits as its factorization.

2638661381 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 248832, while the sum is 44.

The square root of 2638661381 is about 51367.9022444951. The cubic root of 2638661381 is about 1381.8510099477.

The spelling of 2638661381 in words is "two billion, six hundred thirty-eight million, six hundred sixty-one thousand, three hundred eighty-one".