1556651001 has 4 divisors (see below), whose sum is σ = 2075534672. Its totient is φ = 1037767332.

The previous prime is 1556650987. The next prime is 1556651003. The reversal of 1556651001 is 1001566551.

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.

It is not a de Polignac number, because 1556651001 - 2²³ = 1548262393 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1556651001.

It is not an unprimeable number, because it can be changed into a prime (1556651003) 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, 259441831 + ... + 259441836.

It is an arithmetic number, because the mean of its divisors is an integer number (518883668).

Almost surely, 2^1556651001 is an apocalyptic number.

It is an amenable number.

1556651001 is a deficient number, since it is larger than the sum of its proper divisors (518883671).

1556651001 is an equidigital number, since it uses as much as digits as its factorization.

1556651001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 518883670.

The product of its (nonzero) digits is 4500, while the sum is 30.

The square root of 1556651001 is about 39454.4167489522. The cubic root of 1556651001 is about 1158.9474700145.

The spelling of 1556651001 in words is "one billion, five hundred fifty-six million, six hundred fifty-one thousand, one".