77142780 has 336 divisors, whose sum is σ = 293063904. Its totient is φ = 16796160.

The previous prime is 77142763. The next prime is 77142781. The reversal of 77142780 is 8724177.

It is a super-2 number, since 2×77142780² = 11902017012256800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (77142781) by changing a digit.

It is a polite number, since it can be written in 111 ways as a sum of consecutive naturals, for example, 2084922 + ... + 2084958.

It is an arithmetic number, because the mean of its divisors is an integer number (872214).

Almost surely, 2^77142780 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 77142780, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (146531952).

77142780 is an abundant number, since it is smaller than the sum of its proper divisors (215921124).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

77142780 is a wasteful number, since it uses less digits than its factorization.

77142780 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 88 (or 71 counting only the distinct ones).

The product of its (nonzero) digits is 21952, while the sum is 36.

The square root of 77142780 is about 8783.0962649854. The cubic root of 77142780 is about 425.6948816927.

The spelling of 77142780 in words is "seventy-seven million, one hundred forty-two thousand, seven hundred eighty".