11901781 has 2 divisors, whose sum is σ = 11901782. Its totient is φ = 11901780.

The previous prime is 11901761. The next prime is 11901811. The reversal of 11901781 is 18710911.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11458225 + 443556 = 3385^2 + 666^2 .

It is an emirp because it is prime and its reverse (18710911) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 11901781 - 2⁵ = 11901749 is a prime.

It is a super-2 number, since 2×11901781² = 283304781943922, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (11901761) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5950890 + 5950891.

It is an arithmetic number, because the mean of its divisors is an integer number (5950891).

Almost surely, 2^11901781 is an apocalyptic number.

It is an amenable number.

11901781 is a deficient number, since it is larger than the sum of its proper divisors (1).

11901781 is an equidigital number, since it uses as much as digits as its factorization.

11901781 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 504, while the sum is 28.

The square root of 11901781 is about 3449.8957955277. The cubic root of 11901781 is about 228.3165105028.

The spelling of 11901781 in words is "eleven million, nine hundred one thousand, seven hundred eighty-one".