361815781 has 4 divisors (see below), whose sum is σ = 364212064. Its totient is φ = 359419500.

The previous prime is 361815757. The next prime is 361815809. The reversal of 361815781 is 187518163.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 361815781 - 2⁷ = 361815653 is a prime.

It is a super-2 number, since 2×361815781² = 261821318761279922, which 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 (361815721) 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, 1197915 + ... + 1198216.

It is an arithmetic number, because the mean of its divisors is an integer number (91053016).

Almost surely, 2^361815781 is an apocalyptic number.

It is an amenable number.

361815781 is a deficient number, since it is larger than the sum of its proper divisors (2396283).

361815781 is a wasteful number, since it uses less digits than its factorization.

361815781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2396282.

The product of its digits is 40320, while the sum is 40.

The square root of 361815781 is about 19021.4558065359. The cubic root of 361815781 is about 712.5726814540.

The spelling of 361815781 in words is "three hundred sixty-one million, eight hundred fifteen thousand, seven hundred eighty-one".