1561266615 has 32 divisors (see below), whose sum is σ = 2574565056. Its totient is φ = 807321600.

The previous prime is 1561266599. The next prime is 1561266617. The reversal of 1561266615 is 5166621651.

It is not a de Polignac number, because 1561266615 - 2⁴ = 1561266599 is a prime.

It is a super-2 number, since 2×1561266615² = 4875106886227116450, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1561266617) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 157815 + ... + 167415.

It is an arithmetic number, because the mean of its divisors is an integer number (80455158).

Almost surely, 2^1561266615 is an apocalyptic number.

1561266615 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

1561266615 is a deficient number, since it is larger than the sum of its proper divisors (1013298441).

1561266615 is a wasteful number, since it uses less digits than its factorization.

1561266615 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9939.

The product of its digits is 64800, while the sum is 39.

The square root of 1561266615 is about 39512.8664487911. The cubic root of 1561266615 is about 1160.0918018409.

It can be divided in two parts, 15 and 61266615, that multiplied together give a square (918999225 = 30315²).

The spelling of 1561266615 in words is "one billion, five hundred sixty-one million, two hundred sixty-six thousand, six hundred fifteen".