1561215 has 32 divisors (see below), whose sum is σ = 2681280. Its totient is φ = 774144.

The previous prime is 1561213. The next prime is 1561243. The reversal of 1561215 is 5121651.

It is not a de Polignac number, because 1561215 - 2¹ = 1561213 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1561191 and 1561200.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1561213) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 16047 + ... + 16143.

It is an arithmetic number, because the mean of its divisors is an integer number (83790).

2^1561215 is an apocalyptic number.

1561215 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

1561215 is a deficient number, since it is larger than the sum of its proper divisors (1120065).

1561215 is a wasteful number, since it uses less digits than its factorization.

1561215 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 171.

The product of its digits is 300, while the sum is 21.

The square root of 1561215 is about 1249.4858942781. The cubic root of 1561215 is about 116.0079017606.

Adding to 1561215 its reverse (5121651), we get a palindrome (6682866).

The spelling of 1561215 in words is "one million, five hundred sixty-one thousand, two hundred fifteen".