1051240021 has 8 divisors (see below), whose sum is σ = 1134878360. Its totient is φ = 967997952.

The previous prime is 1051240019. The next prime is 1051240027. The reversal of 1051240021 is 1200421501.

It can be written as a sum of positive squares in 4 ways, for example, as 121660900 + 929579121 = 11030^2 + 30489^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1051240021 - 2¹ = 1051240019 is a prime.

It is a super-2 number, since 2×1051240021² = 2210211163504160882, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1051239977 and 1051240004.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1051240027) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 93540 + ... + 104173.

It is an arithmetic number, because the mean of its divisors is an integer number (141859795).

Almost surely, 2^1051240021 is an apocalyptic number.

It is an amenable number.

1051240021 is a deficient number, since it is larger than the sum of its proper divisors (83638339).

1051240021 is a wasteful number, since it uses less digits than its factorization.

1051240021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 198135.

The product of its (nonzero) digits is 80, while the sum is 16.

The square root of 1051240021 is about 32422.8317856414. The cubic root of 1051240021 is about 1016.7963114195.

Adding to 1051240021 its reverse (1200421501), we get a palindrome (2251661522).

The spelling of 1051240021 in words is "one billion, fifty-one million, two hundred forty thousand, twenty-one".