1247653561 has 32 divisors (see below), whose sum is σ = 1627895808. Its totient is φ = 927210240.

The previous prime is 1247653543. The next prime is 1247653571. The reversal of 1247653561 is 1653567421.

It is not a de Polignac number, because 1247653561 - 2⁵ = 1247653529 is a prime.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is not an unprimeable number, because it can be changed into a prime (1247653501) 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, 766030 + ... + 767656.

It is an arithmetic number, because the mean of its divisors is an integer number (50871744).

Almost surely, 2^1247653561 is an apocalyptic number.

1247653561 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1247653561 is a deficient number, since it is larger than the sum of its proper divisors (380242247).

1247653561 is a wasteful number, since it uses less digits than its factorization.

1247653561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2101.

The product of its digits is 151200, while the sum is 40.

The square root of 1247653561 is about 35322.1398134371. The cubic root of 1247653561 is about 1076.5428895441.

The spelling of 1247653561 in words is "one billion, two hundred forty-seven million, six hundred fifty-three thousand, five hundred sixty-one".