261622403381 has 4 divisors (see below), whose sum is σ = 261860893452. Its totient is φ = 261383913312.

The previous prime is 261622403327. The next prime is 261622403411. The reversal of 261622403381 is 183304226162.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 54319760356 + 207302643025 = 233066^2 + 455305^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-261622403381 is a prime.

It is a super-2 number, since 2×261622403381² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261622403321) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 119243390 + ... + 119245583.

It is an arithmetic number, because the mean of its divisors is an integer number (65465223363).

Almost surely, 2^261622403381 is an apocalyptic number.

It is an amenable number.

261622403381 is a deficient number, since it is larger than the sum of its proper divisors (238490071).

261622403381 is a wasteful number, since it uses less digits than its factorization.

261622403381 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 238490070.

The product of its (nonzero) digits is 82944, while the sum is 38.

The spelling of 261622403381 in words is "two hundred sixty-one billion, six hundred twenty-two million, four hundred three thousand, three hundred eighty-one".