1261533406 has 32 divisors (see below), whose sum is σ = 2249533440. Its totient is φ = 519199200.

The previous prime is 1261533347. The next prime is 1261533479. The reversal of 1261533406 is 6043351621.

It is a Harshad number since it is a multiple of its sum of digits (31).

It is a congruent number.

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 45760 + ... + 67948.

It is an arithmetic number, because the mean of its divisors is an integer number (70297920).

Almost surely, 2^1261533406 is an apocalyptic number.

1261533406 is a deficient number, since it is larger than the sum of its proper divisors (988000034).

1261533406 is a wasteful number, since it uses less digits than its factorization.

1261533406 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22360.

The product of its (nonzero) digits is 12960, while the sum is 31.

The square root of 1261533406 is about 35518.0715411183. The cubic root of 1261533406 is about 1080.5202700197.

The spelling of 1261533406 in words is "one billion, two hundred sixty-one million, five hundred thirty-three thousand, four hundred six".