1091002021 has 4 divisors (see below), whose sum is σ = 1148423200. Its totient is φ = 1033580844.

The previous prime is 1091002007. The next prime is 1091002057. The reversal of 1091002021 is 1202001901.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 1202001901 = 13487 ⋅89123.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1091002021 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1091001986 and 1091002004.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1091002061) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 28710561 + ... + 28710598.

It is an arithmetic number, because the mean of its divisors is an integer number (287105800).

Almost surely, 2^1091002021 is an apocalyptic number.

It is an amenable number.

1091002021 is a deficient number, since it is larger than the sum of its proper divisors (57421179).

1091002021 is an equidigital number, since it uses as much as digits as its factorization.

1091002021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 57421178.

The product of its (nonzero) digits is 36, while the sum is 16.

The square root of 1091002021 is about 33030.3197229455. The cubic root of 1091002021 is about 1029.4577285070.

Adding to 1091002021 its reverse (1202001901), we get a palindrome (2293003922).

The spelling of 1091002021 in words is "one billion, ninety-one million, two thousand, twenty-one".