1981254551 has 2 divisors, whose sum is σ = 1981254552. Its totient is φ = 1981254550.

The previous prime is 1981254463. The next prime is 1981254557. The reversal of 1981254551 is 1554521891.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1981254551 is a prime.

It is a super-3 number, since 3×1981254551³ (a number of 29 digits) contains 333 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 1981254499 and 1981254508.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1981254557) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 990627275 + 990627276.

It is an arithmetic number, because the mean of its divisors is an integer number (990627276).

Almost surely, 2^1981254551 is an apocalyptic number.

1981254551 is a deficient number, since it is larger than the sum of its proper divisors (1).

1981254551 is an equidigital number, since it uses as much as digits as its factorization.

1981254551 is an evil number, because the sum of its binary digits is even.

The product of its digits is 72000, while the sum is 41.

The square root of 1981254551 is about 44511.2856588079. The cubic root of 1981254551 is about 1255.9723898805.

The spelling of 1981254551 in words is "one billion, nine hundred eighty-one million, two hundred fifty-four thousand, five hundred fifty-one".