1561651 has 12 divisors (see below), whose sum is σ = 1936816. Its totient is φ = 1226160.

The previous prime is 1561639. The next prime is 1561657.

1561651 is nontrivially palindromic in base 10.

It is not a de Polignac number, because 1561651 - 2⁹ = 1561139 is a prime.

1561651 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (1561657) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 11856 + ... + 11986.

2^1561651 is an apocalyptic number.

1561651 is a deficient number, since it is larger than the sum of its proper divisors (375165).

1561651 is an equidigital number, since it uses as much as digits as its factorization.

1561651 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 282 (or 151 counting only the distinct ones).

The product of its digits is 900, while the sum is 25.

The square root of 1561651 is about 1249.6603538562. The cubic root of 1561651 is about 116.0186999183.

The spelling of 1561651 in words is "one million, five hundred sixty-one thousand, six hundred fifty-one".