78155261 has 16 divisors (see below), whose sum is σ = 82814400. Its totient is φ = 73653888.

The previous prime is 78155249. The next prime is 78155269. The reversal of 78155261 is 16255187.

It is a cyclic number.

It is not a de Polignac number, because 78155261 - 2¹⁴ = 78138877 is a prime.

It is a super-2 number, since 2×78155261² = 12216489643956242, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78155269) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 276026 + ... + 276308.

It is an arithmetic number, because the mean of its divisors is an integer number (5175900).

Almost surely, 2^78155261 is an apocalyptic number.

It is an amenable number.

78155261 is a deficient number, since it is larger than the sum of its proper divisors (4659139).

78155261 is a wasteful number, since it uses less digits than its factorization.

78155261 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 508.

The product of its digits is 16800, while the sum is 35.

The square root of 78155261 is about 8840.5464197639. The cubic root of 78155261 is about 427.5491748318.

The spelling of 78155261 in words is "seventy-eight million, one hundred fifty-five thousand, two hundred sixty-one".