21507007246661 has 16 divisors (see below), whose sum is σ = 23061012076800. Its totient is φ = 19985114992128.

The previous prime is 21507007246651. The next prime is 21507007246691. The reversal of 21507007246661 is 16664270070512.

It is a cyclic number.

It is not a de Polignac number, because 21507007246661 - 2¹⁴ = 21507007230277 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21507007246651) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 53739545 + ... + 54138273.

It is an arithmetic number, because the mean of its divisors is an integer number (1441313254800).

Almost surely, 2^{21507007246661} is an apocalyptic number.

It is an amenable number.

21507007246661 is a deficient number, since it is larger than the sum of its proper divisors (1554004830139).

21507007246661 is a wasteful number, since it uses less digits than its factorization.

21507007246661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 438988.

The product of its (nonzero) digits is 846720, while the sum is 47.

The spelling of 21507007246661 in words is "twenty-one trillion, five hundred seven billion, seven million, two hundred forty-six thousand, six hundred sixty-one".