77451978 has 32 divisors (see below), whose sum is σ = 158731776. Its totient is φ = 25187328.

The previous prime is 77451973. The next prime is 77452003. The reversal of 77451978 is 87915477.

It is a super-2 number, since 2×77451978² = 11997617792224968, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (77451973) 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, 41575 + ... + 43397.

It is an arithmetic number, because the mean of its divisors is an integer number (4960368).

Almost surely, 2^77451978 is an apocalyptic number.

77451978 is an abundant number, since it is smaller than the sum of its proper divisors (81279798).

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

77451978 is a wasteful number, since it uses less digits than its factorization.

77451978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1998.

The product of its digits is 493920, while the sum is 48.

The square root of 77451978 is about 8800.6805418672. The cubic root of 77451978 is about 426.2628697851.

The spelling of 77451978 in words is "seventy-seven million, four hundred fifty-one thousand, nine hundred seventy-eight".