1261205451 has 32 divisors (see below), whose sum is σ = 2066269440. Its totient is φ = 753883200.

The previous prime is 1261205443. The next prime is 1261205459. The reversal of 1261205451 is 1545021621.

1261205451 is a `hidden beast` number, since 1 + 2 + 6 + 1 + 205 + 451 = 666.

It is an interprime number because it is at equal distance from previous prime (1261205443) and next prime (1261205459).

It is not a de Polignac number, because 1261205451 - 2³ = 1261205443 is a prime.

It is a super-2 number, since 2×1261205451² = 3181278379264226802, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (1261205459) 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, 7405 + ... + 50766.

It is an arithmetic number, because the mean of its divisors is an integer number (64570920).

Almost surely, 2^1261205451 is an apocalyptic number.

1261205451 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

1261205451 is a deficient number, since it is larger than the sum of its proper divisors (805063989).

1261205451 is a wasteful number, since it uses less digits than its factorization.

1261205451 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 58264 (or 58258 counting only the distinct ones).

The product of its (nonzero) digits is 2400, while the sum is 27.

The square root of 1261205451 is about 35513.4545067077. The cubic root of 1261205451 is about 1080.4266292872.

The spelling of 1261205451 in words is "one billion, two hundred sixty-one million, two hundred five thousand, four hundred fifty-one".