21501157726642 has 12 divisors (see below), whose sum is σ = 35450255921598. Its totient is φ = 9773253512000.

The previous prime is 21501157726639. The next prime is 21501157726663. The reversal of 21501157726642 is 24662775110512.

It can be written as a sum of positive squares in only one way, i.e., 19050614819401 + 2450542907241 = 4364701^2 + 1565421^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 44423879359 + ... + 44423879842.

Almost surely, 2^{21501157726642} is an apocalyptic number.

21501157726642 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

21501157726642 is a deficient number, since it is larger than the sum of its proper divisors (13949098194956).

21501157726642 is a wasteful number, since it uses less digits than its factorization.

21501157726642 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 88847759225 (or 88847759214 counting only the distinct ones).

The product of its (nonzero) digits is 1411200, while the sum is 49.

The spelling of 21501157726642 in words is "twenty-one trillion, five hundred one billion, one hundred fifty-seven million, seven hundred twenty-six thousand, six hundred forty-two".