21554405901 has 12 divisors (see below), whose sum is σ = 35581876512. Its totient is φ = 12316803336.

The previous prime is 21554405891. The next prime is 21554405947. The reversal of 21554405901 is 10950445512.

21554405901 is a `hidden beast` number, since 2 + 15 + 54 + 4 + 0 + 590 + 1 = 666.

It is not a de Polignac number, because 21554405901 - 2¹⁴ = 21554389517 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21554425901) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 171066651 + ... + 171066776.

It is an arithmetic number, because the mean of its divisors is an integer number (2965156376).

Almost surely, 2^21554405901 is an apocalyptic number.

21554405901 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

21554405901 is a deficient number, since it is larger than the sum of its proper divisors (14027470611).

21554405901 is a wasteful number, since it uses less digits than its factorization.

21554405901 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 342133440 (or 342133437 counting only the distinct ones).

The product of its (nonzero) digits is 36000, while the sum is 36.

The spelling of 21554405901 in words is "twenty-one billion, five hundred fifty-four million, four hundred five thousand, nine hundred one".