21601374476661 has 32 divisors (see below), whose sum is σ = 36840717492480. Its totient is φ = 12253542962688.

The previous prime is 21601374476659. The next prime is 21601374476663. The reversal of 21601374476661 is 16667447310612.

It is an interprime number because it is at equal distance from previous prime (21601374476659) and next prime (21601374476663).

It is not a de Polignac number, because 21601374476661 - 2¹ = 21601374476659 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21601374476598 and 21601374476607.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21601374476663) 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, 417101796 + ... + 417153581.

It is an arithmetic number, because the mean of its divisors is an integer number (1151272421640).

Almost surely, 2^{21601374476661} is an apocalyptic number.

21601374476661 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

21601374476661 is a deficient number, since it is larger than the sum of its proper divisors (15239343015819).

21601374476661 is a wasteful number, since it uses less digits than its factorization.

21601374476661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 834255530 (or 834255524 counting only the distinct ones).

The product of its (nonzero) digits is 6096384, while the sum is 54.

The spelling of 21601374476661 in words is "twenty-one trillion, six hundred one billion, three hundred seventy-four million, four hundred seventy-six thousand, six hundred sixty-one".