21620552400644 has 24 divisors (see below), whose sum is σ = 37846113303936. Its totient is φ = 10807377588000.

The previous prime is 21620552400619. The next prime is 21620552400743. The reversal of 21620552400644 is 44600425502612.

It is a super-2 number, since 2×21620552400644² (a number of 27 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 244004789 + ... + 244093379.

It is an arithmetic number, because the mean of its divisors is an integer number (1576921387664).

Almost surely, 2^{21620552400644} is an apocalyptic number.

It is an amenable number.

21620552400644 is a deficient number, since it is larger than the sum of its proper divisors (16225560903292).

21620552400644 is a wasteful number, since it uses less digits than its factorization.

21620552400644 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 104267 (or 104265 counting only the distinct ones).

The product of its (nonzero) digits is 460800, while the sum is 41.

The spelling of 21620552400644 in words is "twenty-one trillion, six hundred twenty billion, five hundred fifty-two million, four hundred thousand, six hundred forty-four".