1421991551 has 2 divisors, whose sum is σ = 1421991552. Its totient is φ = 1421991550.

The previous prime is 1421991541. The next prime is 1421991569. The reversal of 1421991551 is 1551991241.

It is a happy number.

It is a weak prime.

It is an emirp because it is prime and its reverse (1551991241) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1421991551 is a prime.

It is a super-2 number, since 2×1421991551² = 4044119942230771202, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1421991541) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 710995775 + 710995776.

It is an arithmetic number, because the mean of its divisors is an integer number (710995776).

Almost surely, 2^1421991551 is an apocalyptic number.

1421991551 is a deficient number, since it is larger than the sum of its proper divisors (1).

1421991551 is an equidigital number, since it uses as much as digits as its factorization.

1421991551 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 16200, while the sum is 38.

The square root of 1421991551 is about 37709.3032420383. The cubic root of 1421991551 is about 1124.5160851430.

The spelling of 1421991551 in words is "one billion, four hundred twenty-one million, nine hundred ninety-one thousand, five hundred fifty-one".