156221371801 has 32 divisors (see below), whose sum is σ = 176958835200. Its totient is φ = 136670976000.

The previous prime is 156221371777. The next prime is 156221371807. The reversal of 156221371801 is 108173122651.

It is a 4-Lehmer number, since φ(156221371801) divides (156221371801-1)⁴.

It is a cyclic number.

It is not a de Polignac number, because 156221371801 - 2¹⁵ = 156221339033 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (156221371807) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 72290161 + ... + 72292321.

It is an arithmetic number, because the mean of its divisors is an integer number (5529963600).

Almost surely, 2^156221371801 is an apocalyptic number.

156221371801 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

156221371801 is the 176761-st centered decagonal number.

It is an amenable number.

156221371801 is a deficient number, since it is larger than the sum of its proper divisors (20737463399).

156221371801 is a wasteful number, since it uses less digits than its factorization.

156221371801 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4321.

The product of its (nonzero) digits is 20160, while the sum is 37.

The spelling of 156221371801 in words is "one hundred fifty-six billion, two hundred twenty-one million, three hundred seventy-one thousand, eight hundred one".