77121261 has 16 divisors (see below), whose sum is σ = 130576000. Its totient is φ = 44069184.

The previous prime is 77121251. The next prime is 77121271. The reversal of 77121261 is 16212177.

It is an interprime number because it is at equal distance from previous prime (77121251) and next prime (77121271).

It is not a de Polignac number, because 77121261 - 2²¹ = 75024109 is a prime.

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

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (77121241) 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, 203836 + ... + 204213.

It is an arithmetic number, because the mean of its divisors is an integer number (8161000).

Almost surely, 2^77121261 is an apocalyptic number.

It is an amenable number.

77121261 is a deficient number, since it is larger than the sum of its proper divisors (53454739).

77121261 is a wasteful number, since it uses less digits than its factorization.

77121261 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 408065 (or 408059 counting only the distinct ones).

The product of its digits is 1176, while the sum is 27.

The square root of 77121261 is about 8781.8711559667. The cubic root of 77121261 is about 425.6552954430.

The spelling of 77121261 in words is "seventy-seven million, one hundred twenty-one thousand, two hundred sixty-one".