1891501231 has 2 divisors, whose sum is σ = 1891501232. Its totient is φ = 1891501230.

The previous prime is 1891501159. The next prime is 1891501279. The reversal of 1891501231 is 1321051981.

It is a strong prime.

It is an emirp because it is prime and its reverse (1321051981) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1891501231 - 2⁷ = 1891501103 is a prime.

It is a super-2 number, since 2×1891501231² = 7155553813749030722, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 1891501193 and 1891501202.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1891501331) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 945750615 + 945750616.

It is an arithmetic number, because the mean of its divisors is an integer number (945750616).

Almost surely, 2^1891501231 is an apocalyptic number.

1891501231 is a deficient number, since it is larger than the sum of its proper divisors (1).

1891501231 is an equidigital number, since it uses as much as digits as its factorization.

1891501231 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2160, while the sum is 31.

The square root of 1891501231 is about 43491.3926081932. The cubic root of 1891501231 is about 1236.7128578716.

The spelling of 1891501231 in words is "one billion, eight hundred ninety-one million, five hundred one thousand, two hundred thirty-one".