1261623501 has 12 divisors (see below), whose sum is σ = 1856729628. Its totient is φ = 825212544.

The previous prime is 1261623497. The next prime is 1261623509. The reversal of 1261623501 is 1053261621.

1261623501 is a `hidden beast` number, since 12 + 616 + 2 + 35 + 0 + 1 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 370601001 + 891022500 = 19251^2 + 29850^2 .

It is not a de Polignac number, because 1261623501 - 2² = 1261623497 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1261623509) 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, 1321980 + ... + 1322933.

It is an arithmetic number, because the mean of its divisors is an integer number (154727469).

Almost surely, 2^1261623501 is an apocalyptic number.

It is an amenable number.

1261623501 is a deficient number, since it is larger than the sum of its proper divisors (595106127).

1261623501 is a wasteful number, since it uses less digits than its factorization.

1261623501 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2644972 (or 2644969 counting only the distinct ones).

The product of its (nonzero) digits is 2160, while the sum is 27.

The square root of 1261623501 is about 35519.3398165000. The cubic root of 1261623501 is about 1080.5459919324.

The spelling of 1261623501 in words is "one billion, two hundred sixty-one million, six hundred twenty-three thousand, five hundred one".