78540288157221 has 64 divisors (see below), whose sum is σ = 119653561221120. Its totient is φ = 45390425472000.

The previous prime is 78540288157213. The next prime is 78540288157291. The reversal of 78540288157221 is 12275188204587.

It is not a de Polignac number, because 78540288157221 - 2³ = 78540288157213 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78540288157211) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 129638221 + ... + 130242653.

It is an arithmetic number, because the mean of its divisors is an integer number (1869586894080).

Almost surely, 2^{78540288157221} is an apocalyptic number.

78540288157221 is a gapful number since it is divisible by the number (71) formed by its first and last digit.

It is an amenable number.

78540288157221 is a deficient number, since it is larger than the sum of its proper divisors (41113273063899).

78540288157221 is a wasteful number, since it uses less digits than its factorization.

78540288157221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 606338.

The product of its (nonzero) digits is 20070400, while the sum is 60.

The spelling of 78540288157221 in words is "seventy-eight trillion, five hundred forty billion, two hundred eighty-eight million, one hundred fifty-seven thousand, two hundred twenty-one".