1287429021 has 6 divisors (see below), whose sum is σ = 1859619710. Its totient is φ = 858286008.

The previous prime is 1287428993. The next prime is 1287429079. The reversal of 1287429021 is 1209247821.

It can be written as a sum of positive squares in only one way, i.e., 1240025796 + 47403225 = 35214^2 + 6885^2 .

It is not a de Polignac number, because 1287429021 - 2⁶ = 1287428957 is a prime.

It is a super-2 number, since 2×1287429021² = 3314946968226036882, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1287429821) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 71523826 + ... + 71523843.

Almost surely, 2^1287429021 is an apocalyptic number.

It is an amenable number.

1287429021 is a deficient number, since it is larger than the sum of its proper divisors (572190689).

1287429021 is a wasteful number, since it uses less digits than its factorization.

1287429021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 143047675 (or 143047672 counting only the distinct ones).

The product of its (nonzero) digits is 16128, while the sum is 36.

The square root of 1287429021 is about 35880.7611541338. The cubic root of 1287429021 is about 1087.8635651641.

The spelling of 1287429021 in words is "one billion, two hundred eighty-seven million, four hundred twenty-nine thousand, twenty-one".